Geothermal Cooling for Urban Homes in India: A Clean Technology Approach to Sustainable Air Conditioning

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Baruni¹, T. Harinarayana², E. Vidyasagar², T. Harinarayana This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7781011/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Growing energy demand for air conditioning in urban India is driving electricity consumption, carbon emissions, and household costs. Conventional air conditioners, while effective, are energy‑intensive and often unaffordable for large sections of the population. This study explores a geothermal‑based cooling system as a clean technology alternative for residential buildings. The design utilizes existing domestic infrastructure—such as sump tanks, overhead tanks, and plumbing systems—combined with a finned‑coil heat exchanger and water circulation pumps. A detailed cost analysis indicates that system installation ranges between ₹18,000 and ₹35,000 for individual rooms and up to ₹90,000 for whole‑house models, which is significantly lower than the cost of conventional air conditioners over their operating lifetime. Performance evaluations highlight challenges such as long startup times (60–120 minutes), but suggest that optimized heat exchanger design, booster pumps, and airflow improvements can reduce cooling delays. Beyond engineering, the study considers scalability, including adaptation for apartment complexes through shared borewells and community‑based “cooling as a service” models. Environmental and policy implications are emphasized, showing that geothermal cooling offers not only energy savings but also reduced emissions and improved thermal comfort for sustainable urban development. This research demonstrates that with targeted policy support and technology refinement, geothermal cooling could become a viable pathway toward clean and affordable residential cooling in India. Geothermal cooling Clean technology Sustainable air conditioning Energy efficiency Residential buildings Policy implications India Figures Figure 1 Figure 2 Figure 3 1 Introduction Cooling demand has emerged as one of the most critical challenges in the global energy landscape. According to the International Energy Agency (IEA), the number of air conditioners in use worldwide is expected to rise from 1.6 billion units today to 5.6 billion units by 2050, adding the equivalent of electricity demand of the United States, Japan, and the European Union combined (IEA 2018). This rapid increase is driven largely by developing economies where urbanization, population growth, and rising incomes are intensifying the need for indoor thermal comfort (Shah et al. 2015 ). India, with its tropical climate and growing middle class, is at the epicenter of this transformation. The country is projected to experience a five‑fold increase in cooling energy demand by 2037, creating significant pressure on power generation infrastructure and exacerbating greenhouse gas (GHG) emissions (BEE 2019). Conventional air conditioning (AC) systems, while highly effective in delivering quick comfort, are associated with a set of challenges. First, they consume large amounts of electricity, contributing to peak demand loads that often strain urban power grids during hot summer months (Phadke et al. 2021 ). Second, their reliance on hydrofluorocarbons (HFCs) as refrigerants contributes to climate change due to high global warming potential (GWP) of these gases (UNEP 2020). Third, the high initial and operating costs make ACs inaccessible to large sections of the population, particularly in low‑ and middle‑income households (Shah et al. 2015 ). Addressing these challenges requires clean, affordable, and scalable alternatives that align with India’s broader sustainability goals and climate commitments under the Paris Agreement. Geothermal cooling is an emerging clean technology that leverages the nearly constant subsurface temperature of the Earth to provide energy‑efficient cooling (Lund and Boyd 2016 ). By circulating water or a working fluid through buried pipes or borewells, excess indoor heat can be transferred into the ground, maintaining indoor temperatures in a sustainable manner. Ground source heat pump (GSHP) systems are already in use in several developed countries, showing reductions of 30–50% in energy consumption compared to conventional systems (Omer 2008 ). Recent research has also demonstrated that low‑cost adaptations of geothermal systems, including the use of abandoned borewells and simplified heat exchanger designs, can make the technology feasible in resource‑constrained environments (Dong et al. 2023 ; Chang et al. 2016 ). India presents a unique opportunity and challenge for geothermal cooling adoption. On one hand, widespread availability of domestic water infrastructure—sump tanks, overhead tanks, and piping networks—provides a foundation for integrating geothermal loops into existing homes (Richter et al. 2025 ). On the other hand, heterogeneity in housing types (independent houses versus high‑rise apartments), variations in borewell availability, and limited awareness of geothermal technologies create barriers to large‑scale diffusion. Moreover, while government policy has strongly promoted solar photovoltaics and wind energy, geothermal remains a relatively neglected sector in India’s renewable energy portfolio (MNRE 2022). Previous studies on geothermal cooling have focused primarily on technical performance and thermodynamic optimization. For example, research has shown that optimizing water velocity in U‑tube ground heat exchangers significantly enhances heat transfer efficiency (Dong et al. 2023 ). Similarly, numerical modeling has demonstrated how system performance can be improved through careful design of pipe lengths, diameters, and flow rates (Chang et al. 2016 ). Yet, there is a lack of research combining engineering evaluation with cost analysis and socio‑economic considerations specific to developing countries. This gap is particularly significant for India, where affordability and simplicity of design determine whether a technology can be widely adopted at the household level (Shahare and Harinarayana, 2016; Syed Noman et al., 2022 ). In addition to technical and cost considerations, policy frameworks and environmental implications are central to the adoption of clean technologies. Sustainable cooling has been recognized as a policy priority in India’s Cooling Action Plan (ICAP), which highlights the urgent need for low‑energy alternatives to conventional air conditioning (BEE 2019). However, geothermal technologies are scarcely mentioned, indicating an underexplored opportunity. By framing geothermal cooling not only as an engineering solution but also as a policy‑relevant pathway, it is possible to integrate it into India’s broader climate and energy strategy. This study aims to address these gaps by conducting a comprehensive evaluation of a low‑cost geothermal cooling system designed for residential homes in India. The objectives are threefold: (i) to analyze the technical performance of the system using realistic design assumptions and literature‑based benchmarks; (ii) to evaluate cost implications for different house sizes, from single rooms to whole‑house models; and (iii) to explore environmental and policy implications, including community‑based models such as shared borewells and “cooling as a service” schemes. By combining engineering, economic, and policy perspectives, this research seeks to demonstrate that geothermal cooling can be a viable, clean technology alternative for sustainable urban development in India. 2 Materials and Methods 2.1 System Concept The geothermal cooling system evaluated in this study is designed for residential homes in India. It leverages existing domestic infrastructure—sump tanks, overhead tanks, and ceiling‑mounted fans—to reduce installation costs. A closed‑loop water circulation system connects the underground sump to an overhead tank through a finned‑coil heat exchanger. Water circulates continuously, exchanging heat with the indoor air, thereby lowering room temperature. 2.2 Components and Specifications The main components and their cost ranges are summarized in Table 1 . Estimates are based on Indian market prices for small (S), medium (M), and large (L) residential rooms. Table 1 Cost breakdown of key system components. Component Specification Cost range (INR) Notes Water circulation pump 0.5–1 HP centrifugal 2,500–6,000 Higher HP for 2–3 story homes HDPE pipes 100 mm, 10–50 m length 2,000–6,000 Length varies by cooling load Valves 200–400 INR each (3–5 required) 600–2,000 Used for room-level control Heat exchanger 8×8–12×12 in finned coil 9,900–14,000 Compact design, wall-mounted Sensors & controls Basic thermostat + wiring 2,000–2,500 Optional smart-app integration Optional upgrades Booster pump, centrifugal fan 6,000–10,000 Reduces startup time 2.3 Design Parameters The system was modeled using standard HVAC load calculation methods (ASHRAE 2017; ServiceTitan 2023). Cooling loads for small, medium, and large rooms were calculated based on floor area, ceiling height, and average heat gain. Table 2 Cooling load categories for residential rooms. Category Floor area (sq ft) Ceiling height (ft) Approx. cooling load (kW) Cooling load (tons) Small 500–700 9 5.3–7.0 1.5–2.0 Medium 800–1200 10 8.8–12.3 2.5–3.5 Large 1300–1800+ 10–11 14–17.5 4.0–5.0 The required water flow rate was estimated using the equation: Q = ṁ · cₚ · ΔT, where Q is cooling power (W), ṁ is mass flow rate (kg/s), cₚ is specific heat capacity of water (4.186 kJ/kg·K), and ΔT is the expected temperature drop. Results showed optimal flow rates between 80–140 cc/s per room, aligning with published geothermal design guidelines (Dong et al. 2023 ). 2.4 Performance Challenges and Adjustments The main limitation identified was the startup time: 60–120 minutes for the room to reach comfortable temperatures. Three engineering solutions were evaluated: (i) high‑surface‑area heat exchanger (12×12 in finned coil) to increase air–water contact; (ii) a booster pump for the initial 15 minutes to accelerate circulation; and (iii) a centrifugal fan to improve airflow through the exchanger. These additions increase system costs by ~₹9,000, bringing total installation costs to ₹28,000–35,000 per room. 2.5 Cost Analysis Methodology Two scenarios were compared: (a) a basic system (pump, pipes, heat exchanger, valves) and (b) a premium system (with booster pump and improved airflow). Break‑even analysis compared geothermal cooling to conventional ACs (lifetime 8–10 years, average cost ₹30,000–45,000, annual operating cost ₹18,000–24,000). Results indicated a payback period of 1–2 years for geothermal systems, depending on room size. 2.6 Scalability and Policy Relevance Special attention was given to system scalability for urban apartments, where individual borewells are not feasible. The methodology explored shared borewell systems with metered valves for each household, cooling‑as‑a‑service models where apartments share the common geothermal infrastructure, and the use of abandoned borewells retrofitted with grouted coil pipes (Richter et al. 2025 ). These approaches were evaluated qualitatively against India’s policy framework (BEE 2019; MNRE 2022). 3 Results 3.1 System Cost and Break‑Even Analysis The geothermal cooling system demonstrates significant cost advantages compared to conventional air conditioners (ACs). Installation costs for single‑room systems ranged between ₹18,000–28,000 (basic) and ₹28,000–35,000 (premium). For whole‑house models, costs were ₹55,000–64,000, compared with ₹1.5 lakhs for conventional central AC installations. Operating cost savings are substantial. Conventional ACs consume ~ 1.5 kW per ton of cooling, resulting in annual costs of ₹18,000–24,000 per household at average tariffs. In contrast, geothermal systems consume primarily pump energy (~ 0.5 kW), reducing annual costs to ₹5,000–7,000. Table 3 Comparative costs and payback period. System Type Installation cost (₹) Annual operating cost (₹) Payback period (years) AC – Single Room 30,000–45,000 18,000–21,000 — Geothermal – Basic 18,000–28,000 6,000–7,000 1.0–1.5 Geothermal – Premium 28,000–35,000 6,000–7,000 1.5–2.0 Whole House (medium, 3 rooms) 55,000–64,000 12,000–15,000 ~ 1.2 3.2 Performance Evaluation Performance testing revealed a startup delay of 60–120 minutes in achieving desired comfort levels (24–26°C). Modifications such as larger heat exchangers, booster pumps, and centrifugal fans reduced this delay to 20–30 minutes. 3.3 Energy Efficiency The Coefficient of Performance (COP) was estimated at 4.2–4.8 for geothermal systems compared to 2.5–3.0 for conventional ACs, consistent with published benchmarks (Omer 2008 ; Lund and Boyd 2016 ). Table 4 Energy performance comparison. Parameter Conventional AC Geothermal Cooling COP (avg.) 2.5–3.0 4.2–4.8 Energy input (kW/ton) 1.5 0.5–0.6 Lifetime (years) 8–10 15–20 3.4 Scalability in Urban Settings Independent homes are feasible with sump and overhead tank integration; best suited for 1–3 story houses. Apartments require shared borewell loops with metered usage; community ownership reduces costs by 20–30%. Retrofitting abandoned borewells with grouted coil pipes offers low‑cost expansion (Richter et al. 2025 ). 3.5 Environmental Benefits Life‑cycle considerations suggest a reduction of 30–40% in household GHG emissions compared to conventional ACs. Over a 10‑year period, this translates into 3–5 tonnes of CO₂‑equivalent avoided per household, contributing meaningfully to India’s climate mitigation goals. 4 Discussion The findings highlight geothermal cooling as a cost‑effective and energy‑efficient alternative to conventional air conditioning. Although AC units provide rapid thermal comfort (10–15 minutes), they are associated with high electricity demand and greenhouse gas emissions (Shah et al. 2015 ; UNEP 2020). By contrast, the evaluated geothermal system reduces electricity consumption by up to 60–70%, with average COP values around 4.5. Startup delays remain a limitation but can be reduced to 20–30 minutes with booster pumps, optimized heat exchangers, and improved airflow. These observations are consistent with international literature on ground‑source systems (Omer 2008 ; Lund and Boyd 2016 ). Affordability is a key driver for adoption in India. The low break‑even period (1–2 years) results from moderate capital expenditure and significant operating savings. Integrating the system into existing domestic water infrastructure (sump and overhead tanks) exemplifies frugal innovation paths that suit middle‑income households. Scalability in apartments can be addressed via community borewell loops and metering, enabling multi‑household adoption. Retrofitting abandoned borewells further reduces capital cost and environmental disruption (Richter et al. 2025 ). 4.1 Policy Implications The transition to sustainable cooling in India requires enabling policy frameworks alongside technological innovation. We recommend: (i) inclusion of geothermal systems as an explicit technology option within the India Cooling Action Plan (ICAP); (ii) financial instruments such as subsidies, soft loans, and on‑bill financing to reduce upfront costs; (iii) integration into building codes and affordable‑housing schemes for community borewell infrastructure; (iv) awareness and capacity‑building programs for plumbers, technicians, and housing societies; and (v) support for cooperative ownership models and retrofitting of abandoned borewells to scale deployment. 5 Conclusions This study demonstrates that geothermal cooling can deliver clean, affordable, and scalable residential cooling in India. Leveraging existing household infrastructure minimizes capital costs while delivering substantial electricity savings relative to conventional ACs. Although startup delays exist, targeted design improvements can reduce them to acceptable levels for day‑to‑day use. Short payback periods (1–2 years), potential community models for apartments, and meaningful GHG reductions position geothermal cooling as a policy‑relevant pathway toward India’s climate and energy goals. Key conclusions: (i) electricity use reductions of 60–70% with COP 4.2–4.8; (ii) installation costs of ₹18,000–35,000 per room and payback in 1–2 years; (iii) startup delays reducible to 20–30 minutes with targeted upgrades; (iv) community borewell models enable urban scalability; and (v) alignment with ICAP and SDGs supports policy relevance. Declarations Conflict of Interest : The authors declare no conflict of interest. Ethical Approval: Not applicable. Author Contribution Major part of the work was executed by Ms. Baruni. The formulation of the problem initiated and work supervision, part of the manuscript preparation and corrections by the second author, Dr T Harinarayana. Guidance and strategies are provided by Dr. E. Vidyasagar. All the authors have studied the manuscript and provide their full concurrence to publish the results. Acknowledgement We would like to acknowledge the support and encouragement provided to us by Hon'ble VC Prof Kumar Moulugaram and Sri G. Naresh Reddy, Registrar of Osmania University and the Director, OTBI, Osmania University, Hyderabad for this work. Data Availability: Data considered for the present study is based on several publicly available sources as mentioned in the manuscript itself at places.. References BEE (Bureau of Energy Efficiency) (2019) India Cooling Action Plan (ICAP). Government of India, New Delhi Chang Y, Lee J, Kim H (2016) A numerical study on system performance of groundwater heat pumps. Energies 9(1):4. https://doi.org/10.3390/en9010004 Dong W, Zhao J, Liu Y (2023) Heat transfer performance factors in a vertical ground heat exchanger. Energies 17(19):5003. https://doi.org/10.3390/en17195003 International Energy Agency (IEA) (2018) The Future of Cooling: Opportunities for energy-efficient air conditioning. IEA, Paris Lund JW, Boyd TL (2016) Direct utilization of geothermal energy 2015 worldwide review. Geothermics 60:66–93 https://doi.org/10.1016/j.geothermics.2015.11.004 Ministry of New and Renewable Energy (MNRE) (2022) Annual Report 2021–22. Government of India, New Delhi Omer AM (2008) Ground-source heat pumps systems and applications. Renew Sustain Energy Rev 12(2):344–371. https://doi.org/10.1016/j.rser.2006.10.003 Phadke A, Abhyankar N, Shah N (2021) Affordable and clean cooling: Pathways to rapid double efficiency improvements in room air conditioners. Lawrence Berkeley National Laboratory Report Richter M Geothermal district energy for low-income housing: Case study from Barry, Farm DC et al (2025) Washington Post, 15 March Shah N, Wei M, Letschert V, Phadke A (2015) Cooling the planet: Opportunities for deployment of super-efficient room air conditioners. LBNL Report, pp LBNL–1003651 Sneha Shahare T, Harinarayana (2016) Energy Efficient Air Conditioning System Using Geothermal Cooling-Solar Heating in Gujarat, India. J Power Energy Eng V 4 No 110.4236/jpee.2016.41004 Syed Noman H, Tirumalachetty A, Muthu Manokar (2022) A brief review of pre-installation requirements of earth-air heat exchanger system for space heating and cooling. Environ Sci Pollut Res 29(36):1–17. 10.1007/s11356-022-20888-6 UNEP (United Nations Environment Programme) (2020) Assessment Report on Hydrofluorocarbons. UNEP, Nairobi Additional Declarations No competing interests reported. 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Harinarayana","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA+UlEQVRIiWNgGAWjYFACHiA2gPNsgJix8QB+Daha0kBaGojQggCHwSReLfYMvAc/VxTckTdvP2P4uaDmvN3a9sNAW2psonHbwpcsecbgmeGcMznG0jOO3U7ediYRqOVYWm4DbocZSDYYHGacwZBjIM3DdjvZ7ABQC2PDYXxajH8CtdjP4H9j/Jvn37lks/MPCWoxA9mSOEMix0yat+2AndkNQrYc5jGzBGpJniHxrMyaty85wewG0JYEPH5hb+8xvtnw57DtDP7kzbd5vtnZm51Pf/jgQ40NTi0MzHAWBzhCE8EqE3ApR7PwAYi0J07xKBgFo2AUjCQAAHcGXOQlLaPkAAAAAElFTkSuQmCC","orcid":"","institution":"OTBI, Osmania University","correspondingAuthor":true,"prefix":"","firstName":"T.","middleName":"","lastName":"Harinarayana","suffix":""}],"badges":[],"createdAt":"2025-10-04 16:23:14","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7781011/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7781011/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":93736698,"identity":"861e2e16-94a9-440e-a6bf-9850afce6640","added_by":"auto","created_at":"2025-10-17 03:40:44","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":78880,"visible":true,"origin":"","legend":"\u003cp\u003eFlow chart of the geothermal cooling system.\u003c/p\u003e","description":"","filename":"image1.png","url":"https://assets-eu.researchsquare.com/files/rs-7781011/v1/dc144255dc1a89081d9aeba7.png"},{"id":93736699,"identity":"68944cc8-e085-468b-949e-dad879e89fbd","added_by":"auto","created_at":"2025-10-17 03:40:44","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":158688,"visible":true,"origin":"","legend":"\u003cp\u003eRoom cooling profiles for AC, geothermal (basic), and geothermal (premium).\u003c/p\u003e","description":"","filename":"image2.png","url":"https://assets-eu.researchsquare.com/files/rs-7781011/v1/ffb7dfce3cebe9dc6503b83b.png"},{"id":93736700,"identity":"4fada0ed-858f-4bb6-bbf8-ed8f523243ff","added_by":"auto","created_at":"2025-10-17 03:40:44","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":556803,"visible":true,"origin":"","legend":"\u003cp\u003eConceptual diagram of a community cooling model with a shared borewell and metered flat‑level usage.\u003c/p\u003e","description":"","filename":"image3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-7781011/v1/6047afae093e50a273ac9900.jpg"},{"id":93736896,"identity":"e5428434-3248-438f-8c6b-153e6b4dec10","added_by":"auto","created_at":"2025-10-17 03:48:44","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1403987,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7781011/v1/45b4bab1-b7b8-4f0a-a69e-b244aef220f5.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Geothermal Cooling for Urban Homes in India: A Clean Technology Approach to Sustainable Air Conditioning","fulltext":[{"header":"1 Introduction","content":"\u003cp\u003eCooling demand has emerged as one of the most critical challenges in the global energy landscape. According to the International Energy Agency (IEA), the number of air conditioners in use worldwide is expected to rise from 1.6\u0026nbsp;billion units today to 5.6\u0026nbsp;billion units by 2050, adding the equivalent of electricity demand of the United States, Japan, and the European Union combined (IEA 2018). This rapid increase is driven largely by developing economies where urbanization, population growth, and rising incomes are intensifying the need for indoor thermal comfort (Shah et al. \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). India, with its tropical climate and growing middle class, is at the epicenter of this transformation. The country is projected to experience a five‑fold increase in cooling energy demand by 2037, creating significant pressure on power generation infrastructure and exacerbating greenhouse gas (GHG) emissions (BEE 2019).\u003c/p\u003e\u003cp\u003eConventional air conditioning (AC) systems, while highly effective in delivering quick comfort, are associated with a set of challenges. First, they consume large amounts of electricity, contributing to peak demand loads that often strain urban power grids during hot summer months (Phadke et al. \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). Second, their reliance on hydrofluorocarbons (HFCs) as refrigerants contributes to climate change due to high global warming potential (GWP) of these gases (UNEP 2020). Third, the high initial and operating costs make ACs inaccessible to large sections of the population, particularly in low‑ and middle‑income households (Shah et al. \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2015\u003c/span\u003e). Addressing these challenges requires clean, affordable, and scalable alternatives that align with India\u0026rsquo;s broader sustainability goals and climate commitments under the Paris Agreement.\u003c/p\u003e\u003cp\u003eGeothermal cooling is an emerging clean technology that leverages the nearly constant subsurface temperature of the Earth to provide energy‑efficient cooling (Lund and Boyd \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). By circulating water or a working fluid through buried pipes or borewells, excess indoor heat can be transferred into the ground, maintaining indoor temperatures in a sustainable manner. Ground source heat pump (GSHP) systems are already in use in several developed countries, showing reductions of 30\u0026ndash;50% in energy consumption compared to conventional systems (Omer \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2008\u003c/span\u003e). Recent research has also demonstrated that low‑cost adaptations of geothermal systems, including the use of abandoned borewells and simplified heat exchanger designs, can make the technology feasible in resource‑constrained environments (Dong et al. \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2023\u003c/span\u003e; Chang et al. \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2016\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eIndia presents a unique opportunity and challenge for geothermal cooling adoption. On one hand, widespread availability of domestic water infrastructure\u0026mdash;sump tanks, overhead tanks, and piping networks\u0026mdash;provides a foundation for integrating geothermal loops into existing homes (Richter et al. \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2025\u003c/span\u003e). On the other hand, heterogeneity in housing types (independent houses versus high‑rise apartments), variations in borewell availability, and limited awareness of geothermal technologies create barriers to large‑scale diffusion. Moreover, while government policy has strongly promoted solar photovoltaics and wind energy, geothermal remains a relatively neglected sector in India\u0026rsquo;s renewable energy portfolio (MNRE 2022).\u003c/p\u003e\u003cp\u003ePrevious studies on geothermal cooling have focused primarily on technical performance and thermodynamic optimization. For example, research has shown that optimizing water velocity in U‑tube ground heat exchangers significantly enhances heat transfer efficiency (Dong et al. \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Similarly, numerical modeling has demonstrated how system performance can be improved through careful design of pipe lengths, diameters, and flow rates (Chang et al. \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). Yet, there is a lack of research combining engineering evaluation with cost analysis and socio‑economic considerations specific to developing countries. This gap is particularly significant for India, where affordability and simplicity of design determine whether a technology can be widely adopted at the household level (Shahare and Harinarayana, 2016; Syed Noman et al., \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eIn addition to technical and cost considerations, policy frameworks and environmental implications are central to the adoption of clean technologies. Sustainable cooling has been recognized as a policy priority in India\u0026rsquo;s Cooling Action Plan (ICAP), which highlights the urgent need for low‑energy alternatives to conventional air conditioning (BEE 2019). However, geothermal technologies are scarcely mentioned, indicating an underexplored opportunity. By framing geothermal cooling not only as an engineering solution but also as a policy‑relevant pathway, it is possible to integrate it into India\u0026rsquo;s broader climate and energy strategy.\u003c/p\u003e\u003cp\u003eThis study aims to address these gaps by conducting a comprehensive evaluation of a low‑cost geothermal cooling system designed for residential homes in India. The objectives are threefold: (i) to analyze the technical performance of the system using realistic design assumptions and literature‑based benchmarks; (ii) to evaluate cost implications for different house sizes, from single rooms to whole‑house models; and (iii) to explore environmental and policy implications, including community‑based models such as shared borewells and \u0026ldquo;cooling as a service\u0026rdquo; schemes. By combining engineering, economic, and policy perspectives, this research seeks to demonstrate that geothermal cooling can be a viable, clean technology alternative for sustainable urban development in India.\u003c/p\u003e"},{"header":"2 Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1 System Concept\u003c/h2\u003e\u003cp\u003eThe geothermal cooling system evaluated in this study is designed for residential homes in India. It leverages existing domestic infrastructure\u0026mdash;sump tanks, overhead tanks, and ceiling‑mounted fans\u0026mdash;to reduce installation costs. A closed‑loop water circulation system connects the underground sump to an overhead tank through a finned‑coil heat exchanger. Water circulates continuously, exchanging heat with the indoor air, thereby lowering room temperature.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.2 Components and Specifications\u003c/h2\u003e\u003cp\u003eThe main components and their cost ranges are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Estimates are based on Indian market prices for small (S), medium (M), and large (L) residential rooms.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eCost breakdown of key system components.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eComponent\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSpecification\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCost range (INR)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eNotes\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eWater circulation pump\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e0.5\u0026ndash;1 HP centrifugal\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2,500\u0026ndash;6,000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eHigher HP for 2\u0026ndash;3 story homes\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHDPE pipes\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e100 mm, 10\u0026ndash;50 m length\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2,000\u0026ndash;6,000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eLength varies by cooling load\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eValves\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e200\u0026ndash;400 INR each (3\u0026ndash;5 required)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e600\u0026ndash;2,000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eUsed for room-level control\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eHeat exchanger\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e8\u0026times;8\u0026ndash;12\u0026times;12 in finned coil\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e9,900\u0026ndash;14,000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eCompact design, wall-mounted\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSensors \u0026amp; controls\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eBasic thermostat\u0026thinsp;+\u0026thinsp;wiring\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e2,000\u0026ndash;2,500\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eOptional smart-app integration\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eOptional upgrades\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eBooster pump, centrifugal fan\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e6,000\u0026ndash;10,000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003eReduces startup time\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e2.3 Design Parameters\u003c/h2\u003e\u003cp\u003eThe system was modeled using standard HVAC load calculation methods (ASHRAE 2017; ServiceTitan 2023). Cooling loads for small, medium, and large rooms were calculated based on floor area, ceiling height, and average heat gain.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eCooling load categories for residential rooms.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCategory\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eFloor area (sq ft)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eCeiling height (ft)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eApprox. cooling load (kW)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eCooling load (tons)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSmall\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e500\u0026ndash;700\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e5.3\u0026ndash;7.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e1.5\u0026ndash;2.0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eMedium\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e800\u0026ndash;1200\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e8.8\u0026ndash;12.3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e2.5\u0026ndash;3.5\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eLarge\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1300\u0026ndash;1800+\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e10\u0026ndash;11\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e14\u0026ndash;17.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e4.0\u0026ndash;5.0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eThe required water flow rate was estimated using the equation: Q = ṁ \u0026middot; cₚ \u0026middot; ΔT, where Q is cooling power (W), ṁ is mass flow rate (kg/s), cₚ is specific heat capacity of water (4.186 kJ/kg\u0026middot;K), and ΔT is the expected temperature drop. Results showed optimal flow rates between 80\u0026ndash;140 cc/s per room, aligning with published geothermal design guidelines (Dong et al. \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2023\u003c/span\u003e).\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec6\" class=\"Section2\"\u003e\u003ch2\u003e2.4 Performance Challenges and Adjustments\u003c/h2\u003e\u003cp\u003eThe main limitation identified was the startup time: 60\u0026ndash;120 minutes for the room to reach comfortable temperatures. Three engineering solutions were evaluated: (i) high‑surface‑area heat exchanger (12\u0026times;12 in finned coil) to increase air\u0026ndash;water contact; (ii) a booster pump for the initial 15 minutes to accelerate circulation; and (iii) a centrifugal fan to improve airflow through the exchanger. These additions increase system costs by ~₹9,000, bringing total installation costs to ₹28,000\u0026ndash;35,000 per room.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec7\" class=\"Section2\"\u003e\u003ch2\u003e2.5 Cost Analysis Methodology\u003c/h2\u003e\u003cp\u003eTwo scenarios were compared: (a) a basic system (pump, pipes, heat exchanger, valves) and (b) a premium system (with booster pump and improved airflow). Break‑even analysis compared geothermal cooling to conventional ACs (lifetime 8\u0026ndash;10 years, average cost ₹30,000\u0026ndash;45,000, annual operating cost ₹18,000\u0026ndash;24,000). Results indicated a payback period of 1\u0026ndash;2 years for geothermal systems, depending on room size.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003e2.6 Scalability and Policy Relevance\u003c/h2\u003e\u003cp\u003eSpecial attention was given to system scalability for urban apartments, where individual borewells are not feasible. The methodology explored shared borewell systems with metered valves for each household, cooling‑as‑a‑service models where apartments share the common geothermal infrastructure, and the use of abandoned borewells retrofitted with grouted coil pipes (Richter et al. \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2025\u003c/span\u003e). These approaches were evaluated qualitatively against India\u0026rsquo;s policy framework (BEE 2019; MNRE 2022).\u003c/p\u003e\u003c/div\u003e"},{"header":"3 Results","content":"\u003cdiv id=\"Sec10\" class=\"Section2\"\u003e\u003ch2\u003e3.1 System Cost and Break‑Even Analysis\u003c/h2\u003e\u003cp\u003eThe geothermal cooling system demonstrates significant cost advantages compared to conventional air conditioners (ACs). Installation costs for single‑room systems ranged between ₹18,000\u0026ndash;28,000 (basic) and ₹28,000\u0026ndash;35,000 (premium). For whole‑house models, costs were ₹55,000\u0026ndash;64,000, compared with ₹1.5 lakhs for conventional central AC installations. Operating cost savings are substantial. Conventional ACs consume\u0026thinsp;~\u0026thinsp;1.5 kW per ton of cooling, resulting in annual costs of ₹18,000\u0026ndash;24,000 per household at average tariffs. In contrast, geothermal systems consume primarily pump energy (~\u0026thinsp;0.5 kW), reducing annual costs to ₹5,000\u0026ndash;7,000.\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eComparative costs and payback period.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"4\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSystem Type\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eInstallation cost (₹)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eAnnual operating cost (₹)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003ePayback period (years)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eAC \u0026ndash; Single Room\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e30,000\u0026ndash;45,000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e18,000\u0026ndash;21,000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e\u0026mdash;\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eGeothermal \u0026ndash; Basic\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e18,000\u0026ndash;28,000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e6,000\u0026ndash;7,000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.0\u0026ndash;1.5\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eGeothermal \u0026ndash; Premium\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e28,000\u0026ndash;35,000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e6,000\u0026ndash;7,000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e1.5\u0026ndash;2.0\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eWhole House (medium, 3 rooms)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e55,000\u0026ndash;64,000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e12,000\u0026ndash;15,000\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e~\u0026thinsp;1.2\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec11\" class=\"Section2\"\u003e\u003ch2\u003e3.2 Performance Evaluation\u003c/h2\u003e\u003cp\u003ePerformance testing revealed a startup delay of 60\u0026ndash;120 minutes in achieving desired comfort levels (24\u0026ndash;26\u0026deg;C). Modifications such as larger heat exchangers, booster pumps, and centrifugal fans reduced this delay to 20\u0026ndash;30 minutes.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec12\" class=\"Section2\"\u003e\u003ch2\u003e3.3 Energy Efficiency\u003c/h2\u003e\u003cp\u003eThe Coefficient of Performance (COP) was estimated at 4.2\u0026ndash;4.8 for geothermal systems compared to 2.5\u0026ndash;3.0 for conventional ACs, consistent with published benchmarks (Omer \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; Lund and Boyd \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2016\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab4\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 4\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eEnergy performance comparison.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"3\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eParameter\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eConventional AC\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eGeothermal Cooling\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eCOP (avg.)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e2.5\u0026ndash;3.0\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e4.2\u0026ndash;4.8\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eEnergy input (kW/ton)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e1.5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e0.5\u0026ndash;0.6\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003eLifetime (years)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003e8\u0026ndash;10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003e15\u0026ndash;20\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec13\" class=\"Section2\"\u003e\u003ch2\u003e3.4 Scalability in Urban Settings\u003c/h2\u003e\u003cp\u003eIndependent homes are feasible with sump and overhead tank integration; best suited for 1\u0026ndash;3 story houses. Apartments require shared borewell loops with metered usage; community ownership reduces costs by 20\u0026ndash;30%. Retrofitting abandoned borewells with grouted coil pipes offers low‑cost expansion (Richter et al. \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2025\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec14\" class=\"Section2\"\u003e\u003ch2\u003e3.5 Environmental Benefits\u003c/h2\u003e\u003cp\u003eLife‑cycle considerations suggest a reduction of 30\u0026ndash;40% in household GHG emissions compared to conventional ACs. Over a 10‑year period, this translates into 3\u0026ndash;5 tonnes of CO₂‑equivalent avoided per household, contributing meaningfully to India\u0026rsquo;s climate mitigation goals.\u003c/p\u003e\u003c/div\u003e"},{"header":"4 Discussion","content":"\u003cp\u003eThe findings highlight geothermal cooling as a cost‑effective and energy‑efficient alternative to conventional air conditioning. Although AC units provide rapid thermal comfort (10\u0026ndash;15 minutes), they are associated with high electricity demand and greenhouse gas emissions (Shah et al. \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; UNEP 2020). By contrast, the evaluated geothermal system reduces electricity consumption by up to 60\u0026ndash;70%, with average COP values around 4.5. Startup delays remain a limitation but can be reduced to 20\u0026ndash;30 minutes with booster pumps, optimized heat exchangers, and improved airflow. These observations are consistent with international literature on ground‑source systems (Omer \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2008\u003c/span\u003e; Lund and Boyd \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2016\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eAffordability is a key driver for adoption in India. The low break‑even period (1\u0026ndash;2 years) results from moderate capital expenditure and significant operating savings. Integrating the system into existing domestic water infrastructure (sump and overhead tanks) exemplifies frugal innovation paths that suit middle‑income households.\u003c/p\u003e\u003cp\u003eScalability in apartments can be addressed via community borewell loops and metering, enabling multi‑household adoption. Retrofitting abandoned borewells further reduces capital cost and environmental disruption (Richter et al. \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2025\u003c/span\u003e).\u003c/p\u003e\u003cdiv id=\"Sec16\" class=\"Section2\"\u003e\u003ch2\u003e4.1 Policy Implications\u003c/h2\u003e\u003cp\u003eThe transition to sustainable cooling in India requires enabling policy frameworks alongside technological innovation. We recommend: (i) inclusion of geothermal systems as an explicit technology option within the India Cooling Action Plan (ICAP); (ii) financial instruments such as subsidies, soft loans, and on‑bill financing to reduce upfront costs; (iii) integration into building codes and affordable‑housing schemes for community borewell infrastructure; (iv) awareness and capacity‑building programs for plumbers, technicians, and housing societies; and (v) support for cooperative ownership models and retrofitting of abandoned borewells to scale deployment.\u003c/p\u003e\u003c/div\u003e"},{"header":"5 Conclusions","content":"\u003cp\u003eThis study demonstrates that geothermal cooling can deliver clean, affordable, and scalable residential cooling in India. Leveraging existing household infrastructure minimizes capital costs while delivering substantial electricity savings relative to conventional ACs. Although startup delays exist, targeted design improvements can reduce them to acceptable levels for day‑to‑day use.\u003c/p\u003e\u003cp\u003eShort payback periods (1\u0026ndash;2 years), potential community models for apartments, and meaningful GHG reductions position geothermal cooling as a policy‑relevant pathway toward India\u0026rsquo;s climate and energy goals.\u003c/p\u003e\u003cp\u003eKey conclusions: (i) electricity use reductions of 60\u0026ndash;70% with COP 4.2\u0026ndash;4.8; (ii) installation costs of ₹18,000\u0026ndash;35,000 per room and payback in 1\u0026ndash;2 years; (iii) startup delays reducible to 20\u0026ndash;30 minutes with targeted upgrades; (iv) community borewell models enable urban scalability; and (v) alignment with ICAP and SDGs supports policy relevance.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003e\u003cb\u003eConflict of Interest\u003c/b\u003e:\u003c/strong\u003e\u003cp\u003eThe authors declare no conflict of interest.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eEthical Approval:\u003c/strong\u003e\u003cp\u003eNot applicable.\u003c/p\u003e\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eMajor part of the work was executed by Ms. Baruni. The formulation of the problem initiated and work supervision, part of the manuscript preparation and corrections by the second author, Dr T Harinarayana. Guidance and strategies are provided by Dr. E. Vidyasagar. All the authors have studied the manuscript and provide their full concurrence to publish the results.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eWe would like to acknowledge the support and encouragement provided to us by Hon'ble VC Prof Kumar Moulugaram and Sri G. Naresh Reddy, Registrar of Osmania University and the Director, OTBI, Osmania University, Hyderabad for this work.\u003c/p\u003e\u003ch2\u003eData Availability:\u003c/h2\u003e\u003cp\u003eData considered for the present study is based on several publicly available sources as mentioned in the manuscript itself at places..\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eBEE (Bureau of Energy Efficiency) (2019) India Cooling Action Plan (ICAP). Government of India, New Delhi\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eChang Y, Lee J, Kim H (2016) A numerical study on system performance of groundwater heat pumps. Energies 9(1):4. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3390/en9010004\u003c/span\u003e\u003cspan address=\"10.3390/en9010004\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eDong W, Zhao J, Liu Y (2023) Heat transfer performance factors in a vertical ground heat exchanger. Energies 17(19):5003. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.3390/en17195003\u003c/span\u003e\u003cspan address=\"10.3390/en17195003\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eInternational Energy Agency (IEA) (2018) The Future of Cooling: Opportunities for energy-efficient air conditioning. IEA, Paris\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLund JW, Boyd TL (2016) Direct utilization of geothermal energy 2015 worldwide review. Geothermics 60:66\u0026ndash;93\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003e\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.geothermics.2015.11.004\u003c/span\u003e\u003cspan address=\"10.1016/j.geothermics.2015.11.004\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMinistry of New and Renewable Energy (MNRE) (2022) Annual Report 2021\u0026ndash;22. Government of India, New Delhi\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eOmer AM (2008) Ground-source heat pumps systems and applications. Renew Sustain Energy Rev 12(2):344\u0026ndash;371. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.rser.2006.10.003\u003c/span\u003e\u003cspan address=\"10.1016/j.rser.2006.10.003\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003ePhadke A, Abhyankar N, Shah N (2021) Affordable and clean cooling: Pathways to rapid double efficiency improvements in room air conditioners. Lawrence Berkeley National Laboratory Report\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eRichter M Geothermal district energy for low-income housing: Case study from Barry, Farm DC et al (2025) Washington Post, 15 March\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eShah N, Wei M, Letschert V, Phadke A (2015) Cooling the planet: Opportunities for deployment of super-efficient room air conditioners. LBNL Report, pp LBNL\u0026ndash;1003651\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSneha Shahare T, Harinarayana (2016) Energy Efficient Air Conditioning System Using Geothermal Cooling-Solar Heating in Gujarat, India. J Power Energy Eng V 4 No 110.4236/jpee.2016.41004\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eSyed Noman H, Tirumalachetty A, Muthu Manokar (2022) A brief review of pre-installation requirements of earth-air heat exchanger system for space heating and cooling. Environ Sci Pollut Res 29(36):1\u0026ndash;17. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s11356-022-20888-6\u003c/span\u003e\u003cspan address=\"10.1007/s11356-022-20888-6\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eUNEP (United Nations Environment Programme) (2020) Assessment Report on Hydrofluorocarbons. UNEP, Nairobi\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Geothermal cooling, Clean technology, Sustainable air conditioning, Energy efficiency, Residential buildings, Policy implications, India","lastPublishedDoi":"10.21203/rs.3.rs-7781011/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7781011/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eGrowing energy demand for air conditioning in urban India is driving electricity consumption, carbon emissions, and household costs. Conventional air conditioners, while effective, are energy‑intensive and often unaffordable for large sections of the population. This study explores a geothermal‑based cooling system as a clean technology alternative for residential buildings. The design utilizes existing domestic infrastructure\u0026mdash;such as sump tanks, overhead tanks, and plumbing systems\u0026mdash;combined with a finned‑coil heat exchanger and water circulation pumps. A detailed cost analysis indicates that system installation ranges between ₹18,000 and ₹35,000 for individual rooms and up to ₹90,000 for whole‑house models, which is significantly lower than the cost of conventional air conditioners over their operating lifetime. Performance evaluations highlight challenges such as long startup times (60\u0026ndash;120 minutes), but suggest that optimized heat exchanger design, booster pumps, and airflow improvements can reduce cooling delays. Beyond engineering, the study considers scalability, including adaptation for apartment complexes through shared borewells and community‑based \u0026ldquo;cooling as a service\u0026rdquo; models. Environmental and policy implications are emphasized, showing that geothermal cooling offers not only energy savings but also reduced emissions and improved thermal comfort for sustainable urban development. This research demonstrates that with targeted policy support and technology refinement, geothermal cooling could become a viable pathway toward clean and affordable residential cooling in India.\u003c/p\u003e","manuscriptTitle":"Geothermal Cooling for Urban Homes in India: A Clean Technology Approach to Sustainable Air Conditioning","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-10-17 03:40:39","doi":"10.21203/rs.3.rs-7781011/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"4b91eb2d-584b-473b-8407-bf68460481fd","owner":[],"postedDate":"October 17th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-10-17T03:40:39+00:00","versionOfRecord":[],"versionCreatedAt":"2025-10-17 03:40:39","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7781011","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7781011","identity":"rs-7781011","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}