Council on Energy, Environment and Water Integrated | International | Independent

RE+: Renewables Beyond Electricity

Solar Air Conditioning & Desalination in India

Poulami Choudhury, Rajeev Palakshappa, Arunabha Ghosh
December 2014 |

Suggested Citation: Choudhury, Poulami, Rajeev Palakshappa, Arunabha Ghosh & Bhaskar Padigala. 2014. RE+: Renewables Beyond Electricity- Solar air conditioning and desalination in India. New Delhi: Council on Energy, Environment and Water and World Wide Fund for Nature.


This report, jointly published with WWF-India, examines two renewable energy technologies - solar air conditioning and solar desalination. It identifies areas of intervention and highlights steps to facilitate large-scale deployment of the two technologies in India.

This study follows a CEEW-WWF 2013 report - RE+ Renewables beyond Electricity - which focused on the status and potential of 14 renewable energy applications.

Projected Scenario for Solar Cooling (Exajoule/yr)

Source: IEA, 2012

Key Findings

Solar Conditioning

  • Cooling (fans, evaporative cooling and air conditioners) accounts for 45 per cent of the total energy consumption in the residential building sector.
  • Heating, Ventilation and Air Conditioning (HVAC) consumes 55 per cent of the total energy utilised in commercial building sector.
  • Solar air-conditioning systems are catering to high-capacity cooling demand in commercial buildings such as retail malls, office spaces, hospitals, convention centres, hotels, etc.
  • Solar applications can be made attractive and economically viable for many food industries, as they require both refrigeration as well as dry heat air for drying products. However, solar air-conditioning systems have been finding it difficult to scale up in their industrial segment.
  • Solar Air-Conditioning Stems do not use harmful refrigerants such as CFC, HCFC or HFC and have multiple benefits ranging from GHG emission reduction to employment generation.
  • Most of the MNRE schemes presently focus on solar collectors and solar thermal driven cooling applications at a large scale.

Solar Desalination

  • Desalination is a process by which dissolved minerals (including salts) are removed from seawater or brackish water. It has also been recognised as a potential solution to India’s limited freshwater reserves.
  • Solar desalination solutions are yet to reach commercial scale and there have been efforts to set up demonstration solar desalination plants in India with the help of government funding and donor finance.
  • Photovoltaic (PV) systems can be used to power RO or ED desalination processes, which are based on electricity as the input energy.
  • Reverse osmosis technology can be used both for brackish water reverse osmosis (BWRO) and seawater reverse osmosis (SWRO).
  • Unit cost of producing desalinated water using solar thermal technology is INR 1.25/litre, while the cost of it using conventional fossil fuel is INR 2/litre.

Key Recommendations

  • Create market demand of solar air conditioning systems through government initiatives and tap alternative funding sources such as CSR and NCEF funds.
  • Create collaborations between stakeholders such as government, training centres, and companies to form necessary human capital.
  • Enhance interface between research agencies and on-ground implementing companies.
  • Promote and disseminate information on renewable energy through dedicated e-portal. Keep documenting the project information, and its performance.
  • Promote subsidy discourse with NABARD and state nodal agencies which can provide accurate information on government schemes for desalination to companies.
  • Foster synergies between government bodies such as the Ministry of Drinking Water & Sanitation, and the Central and State Pollution Control Boards. This could trigger strategies/policies that could integrate solar energy into desalination applications.
  • Explore solutions to contractual and regulatory challenges associated with retrofitting existing fossil-based desalination plants with solar concentrators.

Solar technologies, such as solar air conditioning and desalination, increase resilience against volatile and ever-rising prices of conventional energy sources.

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