Adsorption and Absorption cooling can reduce energy consumption by more than 50% while maintaining performance
Air Conditioning works on the idea of transferring heat from an inside space to a warmer outside environment. Thermodynamic laws state that natural heat transfer can only occur from higher temperature to lower temperatures – think about your hot cup of coffee, if you place your cup down on a surface, that surface will feel warm to the touch after a period of time. That is because the hot coffee is transferring heat to the colder surface, thus cooling down.
With air conditioners, the space we want to cool is the surface in the hot coffee analogy, whereas the warm environment is the hot cup of coffee. We want to transfer heat from a lower temperature space to a higher temperature environment, going against the fundamentals of thermodynamics.
For traditional cooling systems that is where compressors come in. They are used to move a synthetic refrigerant (R-134a) between an evaporator (located inside) and a condenser (located outside). Through this process the temperature of the refrigerant surpasses that of the warm outside environment (T. Refrigerant > T. Warm Environment) which results in the heat absorbed from the inside being rejected in the outside environment – creating a cooling effect inside.
There are a number of drawbacks with Compressor-based cooling that have prompted the development of alternative technologies:
1 – Without the compressor the cooling effect will not occur since heat cannot be naturally transferred from low temperature space to an outside warm environment
2 – Compressors require immense amounts of electricity to operate, more than 50% of the electricity used by an air-conditioner goes towards the compressor
3 – Toxic synthetic refrigerants that contain chlorofluorocarbon or hydrochlorofluorocarbon are used in the system
Alternative cooling technologies differ in how they move the refrigerant between the evaporator and condenser. Chemical reactions between two substances can allow for Thermal Compression (or energy activation) which acts as a direct, non-mechanical, replacement to traditional compressors.
This phenomenon is the foundation of aDsorption & aBsorption cooling technologies, where low-grade heat warms up water to activate nano-porous materials in order to create thermal compression. The low-grade heat can be obtained from exhaust or steam from an industrial process, or heat generated directly from trigeneration systems that use solar panels or CHPs.
Adsorption and absorption chillers have been increasingly gaining popularity due to being a low-energy and sustainable alternative to compressors. They do not emit carbon emissions since they use plain water as a refrigerant, or much heat into the atmosphere. They also use small amounts of electricity since only pumps and fans require electricity; as a result they are a popular solutions for locations where electricity is expensive or not readily available.