Solar Cooling Systems

The growing trend towards installing air-conditioning in buildings places significant pressure on the electricity grid. Solar cooling is a thermally driven cooling process which can help to reduce peak electricity demand caused by air-conditioning or refrigeration needs.

Solar cooling applications

Currently, there are more than one hundred solar cooling systems installed in Europe.

Typical applications can include commercial buildings, such as office buildings and hotels, and food storage including dairy farms.

How solar cooling works

The heat source for the thermally driven cooling process can be provided by solar thermal collectors already commonly used in domestic solar hot water systems.

For more information on solar hot water systems, take a look at the ResourceSmart Sustainable Building Ideas fact sheets.

Solar cooling systems are either closed cycle systems or open cycle systems.

Closed cycle systems produce chilled water which can supply any type of air-conditioning equipment (e.g. air handling units, fan-coils, chilled ceilings).

Open cycle systems, also known as desiccant systems, are a combination of sorptive dehumidification and evaporative cooling to provide fresh air at a comfortable temperature and humidity.

For more technical information visit the website of the Australian Solar Cooling Interest Group (ausSCIG).

Support for solar cooling

Sustainability Victoria is supporting solar cooling by:

  • working collaboratively with CSIRO and The Energy Resources Institute (TERI) in New Delhi, India on a project to design and develop renewable cooling and power generation systems. The project outcomes will be small scale solar-cooling system prototypes
  • using its facilitation expertise and solar heating industry knowledge to analyse barriers to consumer uptake of solar technology in Australia and ensure successful interchange between the Australian and Indian partners
  • investigating opportunities for applications of solar cooling on dairy and fruit farms in Victoria
  • supporting Echuca Regional Health in a project to install solar assisted cooling.

Case study for solar cooling

Echuca in northern Victoria has an excellent solar resource and the solar systems at Echuca Regional Health delivers cooling when it is most needed - on sunny days. As a result the hospital saves money on energy and also on its peak demand for electricity. Annual savings are expected to be about $60,000 per year with greenhouse gas abatement of 1,400 tonnes CO2 eq.

The project also saves investment costs in upgrading the hospitals electricity grid which was under stress due to increased electricity demand caused by rising air-conditioning needs. Savings will increase as energy prices rise. Please read the below case study for further information.

Case study: Echuca Hospital (338KB)
Video - Case study: Echuca Hospital

Investigation - Solar cooling for dairy and fruit farms

Sustainability Victoria has investigated opportunities for more sustainable methods of refrigeration systems on dairy and fruit farms in Victoria.

GenesisNow undertook some of the work on behalf of Sustainability Victoria. They collected and analysed operational farm practices and electricity data at two dairy farms and two fruit cold stores.

Solem Consulting calculated the cooling loads using electricity consumption data of the currently installed refrigeration plant on the farms. The heating loads for the water heating system were also calculated for the dairy farms. This information and data analysis were used to conduct a TRNSYS* simulation. This modelled an alternative solar cooling system and assessed its technical viability for dairy and fruit farms.

The TRNSYS modelling included four design approaches for the solar cooling systems. These were to meet peak cooling load, annual average load, summer average load or a minimal size with a conventional backup system.

The study indicates that the energy savings for the dairy farms could be up to 26% and 9% for the fruit cold stores. The energy savings variation is due to different operational patterns. Cold stores operate continuously during the day and night while dairy farms only operate in the morning and in the afternoon, which is more favourable to solar cooling.

In conclusion, results of this study indicate that the solar cooling potential for dairy farms is more promising than for fruit cold stores.

Please note that this is a preliminary high level study that should not be used as the basis for any technical or investment decisions. All costs and financial analysis are based on estimates only.

*TRNSYS is a software designed to simulate the transient performance of thermal energy systems

Download the study report below:

Document | PDF | 705KB