2016 ASHRAE Winter Conference

This seminar discusses the use of dry and liquid desiccant technologies and how to apply them creatively for the treatment of outside air.  This includes a design that utilizes a combination of cooling tower water, chilled water and hot water that modulates with the outside air loads to either cool or heat the liquid desiccant to provide dehumidification or humidification of the outside air. Then, waste heat or onsite power generation to regenerate the liquid desiccant solution. A comparison of the technologies will be presented and the opportunities for both to provide comfort and energy savings to meet ventilation codes.

Liquid desiccant heat exchangers (LDHX) can improve the performance of many HVAC systems by replacing traditional finned-tube coils. Adding LDHX technology to a vapor compression system effectively raises the evaporator temperature, while still delivering dry air. It also enables separate control of sensible and latent cooling, ensuring occupant comfort in humid climates. This presentation will discuss (1) background on an innovative LDHX design, including a comparison to other liquid desiccant options, (2) modeling and laboratory testing of the LDHX modules, and (3) modeling of a 20-ton dedicated-outdoor air system using these LDHXs.

Air conditioners are made more energy efficient and can provide better humidity control by integrating liquid desiccant heat exchangers. This is the second demonstration of this particular liquid desiccant technology, with lessons learned from the first demonstration being applied to the second demonstration. The new system was completely re-designed from the ground up and has been reduced in size by over 50%. Furthermore, the new design reduces energy use by more than 33%, making the cooling cycle one of the most efficient options available today. This presentation will discuss the system’s new design, cycle improvements, and field test results.

Generation of electricity and air conditioning, one as a byproduct of the other, has the potential to enhance energy efficiency in buildings. In this seminar the potential for integrating fuel cell power systems with liquid desiccant air-conditioning systems is presented. This seminar will point out mutually enhancing features of liquid desiccant and fuel cell systems; provide a state of technology review; and provide details on integrated system performance in various climate and integration conditions.