Liquid desiccant AC system cuts ice rink energy bill

Thanks to a liquid-desiccant air-conditioning system and the use of renewable energy sources, Pines Ice Arena in Pembroke, Florida, claims to have achieved 55% electricity savings, as well as a 35% reduction in natural gas consumption and a 17% decrease in water consumption.

Overall it is expected to reduce annual energy and water costs by over 60%. Previously, Pines Ice Arena, one of the largest ice rinks in South Florida, operated with a standard chiller and dehumidification system, with annual energy bills over USD 389 000 and water bills around USD 31 000. This was replaced by a liquid desiccant system, (six Advantix Duhandling units), located on the roof. Such systems use liquid desiccant material, such as lithium chloride (LiCl) or halide salts to chemically remove moisture and latent heat from process air.  In this case, the liquid desiccant, a non-toxic brine solution, dehumidifies and cleans the air, prior to the cooling operation proper, and releases the humidity outside in the form of water vapour when heated. The system is powered using both waste heat from cogeneration via a microturbine and cooling from a ground-source cooling well.
How does a liquid dessicant air-conditioning system work?

Liquid desiccant AC systems chemically withdraw moisture from the air, prior to cooling, thanks to a liquid desiccant material such as lithium chloride (LiCi) or halide salts. As the operation also involves cooling, it reduces a major part of the thermal charge of the air, before the cooling operation per se. 
Desiccation is provided by two major components: an absorber and a regenerator. In the absorber, previously cooled liquid desiccant is sprayed onto a packed bed of granular particles (which offers a very large contact surface). A counter flow of warm humid air enters the packed bed and its moisture contents are absorbed by the desiccant. The latter is diluted by the absorbed water and then sent to a regenerator in which, the absorbed water is evaporated from the solution, thanks to a heat source (hydrocarbon or gas-fired, recovered, solar, etc.). The newly concentrated desiccant is then cooled in a chiller or a cooling tower, after which it can re-enter the absorber and resume another full cycle.
As the humidity contained in the air contains a certain thermal load, removing it considerably reduces the thermal load the downstream cooling system will have to deal with, thus cutting the actual cooling demand. (Incidentally, part of the cooling operation involved prior to the absorption also removes part of the sensible heat contained in the air, in a way, killing two birds with one stone).

ASHRAE Journal, October 2008