Space Requirements For Powering An Absorption Chiller

By Author: Rockey
Total Articles: 139
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An absorption chiller is a machine that operates on thermodynamic principles to convert the solar thermal energy to air conditioning and refrigeration. Absorption chillers use a thermal compressor instead of a mechanical compressor. The system operates in three phases: evaporation, absorption and regeneration. The first stage involves liquid form refrigerant evaporating low partial pressure surroundings, thereby extracting heat from its environs. The environment in this case is the refrigerator, or space to be cooled. (Note the term refrigerator is used in the thermodynamic context and does not necessarily refer to the appliance.) Following this, the refrigerant is absorbed in gaseous state. This then reduces the partial pressure in the evaporator chamber and further liquid evaporation is now possible. The refrigerant solution is heated to regenerate the cycle, thus evaporating and replenishing the evaporating chamber. It is at this point that solar thermal energy can enter the cycle.
This article will compare the effectiveness of a variety of systems given the task of powering an 800,000 BTU/hr (234 457W) absorption ...
... chiller with the harness solar thermal energy. The solar thermal power input can come from a variety of sources. The solar energy systems compared will be Heliodyne’s GOBI 406 002 flat panels, Apricus’ AP-30 evacuated tube systems, Cogenra’s parabolic trough system and Solartron’s SolarBeam Concentrator. Data used is from publicly available SRCC documents, a solar energy and solar thermal power certification organization. (www.solar-rating.org)
Heliodyne Apricus Cogenra SolarBeam
Gross Area (m2) 2.503 m2 4.158 m2 32.82 m2 15.8 m2
Watts 1613 W 1805 W 20420 W 10772 W
Watts/m2 644 W/m2 434 W/m2 622 W/m2 681 W/m2
Area req’d 364 m2 540 m2 383 m2 344 m2
# of Units req’d 146 130 12 22
(The data above assumes a temperature difference of 15oC between ambient and absorber fluid.)
The SolarBeam Concentrator proves to be the most effective choice for fueling a large absorption chiller. It is more efficient than other tracking concentrator systems on the market. By virtue of its 2-axis solar tracking abilities, it is more efficient than any stationary system. These solar power systems lose efficiency quickly in any situation where the sun’s rays do not form a 90o angle with the absorber. There is only an approximately 2 hour window of peak solar thermal energy efficiency for these systems. Thus for the data above, the number of flat panel and evacuated tube systems presented is the absolute minimum amount required. The actual number would be much higher given the sun’s path across the sky.
Cogenra, the other solar thermal system with tracking capabilities, simply does not have the same power produced per unit area. For every square meter of the system, the SolarBeam can produce 60 more watts. This is very significant when sizing an installation as large as the one required for this absorption chiller. Every step with installing such a system is important, so ensure you have the correct data to make the right choice at every step.
For more information visit www.solartronenergy.com

This is a guest post by James Peter. He is a fairly well-known solar thermal energy and solar tracking abilities Energy.