Solar Thermal Air Conditioning might come off as confusing for some people at first. We tend to associate solar thermal energy with water heating and photovoltaic systems but air conditioning? In actuality, solar thermal air conditioner systems have been around for quite some time.
The most common of course would be air conditioners powered by photovoltaic systems but there are also stand alone systems that make use of absorption chillers that make use of the heat collected from solar energy.
How do Solar Thermal Air-Conditioning Systems Work?
Although there are numerous kinds of solar thermal air-conditioner systems, those that drive closed-loop absorption chillers are the most efficient. Solar energy is typically gathered using solar panels that then heats up water. The heated water is then used to chill water/lithium bromide (depending on the specific system) as it passes through the absorption chiller. Now, the chilled water/lithium bromide is then delivered to a system of copper pipes that have air blowing through them. The resulting cold air produced by this type of passive air conditioning system required no electrical input.
An Inefficient Technology?
Even with all the benefits to be had by getting solar thermal air-conditioner systems, they are still generally considered inefficient compared to conventional ACs. Yes, this also includes systems that make use of closed-loop absorption chillers. Although they’re relative cost has gone down over the years, they’re still expensive enough to deter most homeowners from purchasing. Perhaps the most inefficient of these systems are those that convert solar energy to electricity (photovoltaics).
Top 6 Solar Thermal Air Conditioners
1. Lucy Solar
Shandong Lucy New Energy Technology Ltd’s is a company in China that focuses on making solar thermal air-conditioning solutions. As you’ll see in the video, the company has solutions for almost any type of building/environment (residential houses, schools, hospitals, and office buildings). What’s great about their solutions is that they’re not only for air conditioning but for water heating and other purposes as well. Here is the link to the video:
2. SOPOGY Solar Air Conditioning System
Take note that the likely targets for SOPOGY’s solutions are businesses and industries who want to cut down on their energy consumption. Its solar air conditioning system makes use of the closed-loop absorption chillers and mainly relies on solar thermal energy. However, these solutions are relatively costly and for now are not practical for use in residential units/homes.
This is also a hybrid system much like the ECO Solar Air Conditioning System mentioned earlier. The system promises to provide cooling, heating, and hot water for the home. However, the system is not completely passive and is still reliant on electricity. What’s interesting about it is CSIRO’s decision to hinge the design of this system on the use dessicants instead of a closed-loop absorption chiller.
This residential solution offered by 72 Degrees Heating and Air Conditioning seeks to allow homeowners financial headroom by lowering down their electricity consumption. What’s not clear on the video though is the kind of technology they used. The video does talk about the system’s merits in providing owners with tax credits (federal and state).
You can ignore the alarmist introduction (which actually makes sense) and go straight to Les Hamazaki’s explanation of how the system works. One thing that you might notice with the system though is its size which might not be practical for those living in cities where land area is at a premium. However, take note that the video is 8 years old and there are better options in the market right now. Still, it does paint a good picture of how far solar thermal air conditioners have come in terms of economic viability.
This hybrid system allows for more efficient cooling by boosting the compressor performance of existing conventional air conditioning systems. It mainly acts as an auxiliary compressor that takes off a majority of your main compressor’s workload. This allows you to run your main compressor at lower stages while the system compensates accordingly. As described though, this setup will still use electricity and the solar panel is only there to heat the refrigerant coming from the main compressor.
Solar energy holds a lot of potential as a renewable energy source. Just imagine how many people in underdeveloped and developed countries solar thermal air conditioner systems can help? We can’t expect the technology for making these systems become dirt-cheap overnight. However, if the time does come when solar thermal air-conditioner systems become easier on the pockets to build and install then we might be seeing a marked improvement in the lives of a lot of people who can’t afford to pay for conventional AC systems and the electricity required to run them.
Gordon's expertise in the area of industrial energy efficiency and alternative energy. He is an experienced electrical engineer with a Masters degree in Alternative Energy technology. He is the co-founder of several renewable energy media sites including Solar Thermal Magazine.