The BeCool prototype installed at Oak Ridge National Laboratory for testing in the certified environmental chamber.
Lead Performer: Oak Ridge National Laboratory – Oak Ridge, TN
DOE Total Funding: $500,000
Project Term: October 1, 2017 – September 30, 2020
Funding Type: Lab Award
Project Objective
Conventional dehumidification relies on cooling humid air below the dew point and then reheating the air to the comfort level or thermostatic set point. Humidity is not controlled. The HVAC system turns off when the set point temperature is reached even if the humidity remains elevated beyond a comfortable level, which is energy intensive.
An alternative option is to dehumidify the air using a liquid desiccant (LD) to lessen the air-conditioning load. Liquid desiccants can store dehumidification capacity indefinitely without the need for any thermal insulation. Stored dehumidification capacity is equivalent to air-conditioning capacity, to be used on demand.
Oak Ridge National Laboratory (ORNL) is considering multiple pathways: an air-handler with an LD to remove humidity and developing a fabric made of carbon nano rods.
Project Impact
Using a liquid desiccant for dehumidification will result in a smaller system and less primary energy consumption. In hot-humid climates where air-conditioning loads are high, this method could remove approximately 70% of the latent load, which is the main source of energy consumption for an air-conditioning unit. Controlling humidity by using LDs will result in a higher thermostatic temperature setting that will provide a better comfort level for building occupants while using less energy. LDs also can provide the opportunity for meaningful HVAC load shifting.
Contacts
DOE Technology Manager: Antonio Bouza
Lead Performer: Moonis R. Ally, Oak Ridge National Laboratory
Related Publications
Daniel Betts, Moonis R. Ally, Vishaldeep Sharma, Matthew Tilghman, Matthew Graham, Shyam Mudiraj, Novel Gas-Driven Fuel Cell HVAC and Dehumidification Prototype, 7th International Building Physics Conference, IBPC 2018, Proceedings Syracuse, NY, September 23-26, 2018, pp. 487-492.
Betts, D., Ally, M. R., Mudiraj, S., Tilghman, M., Graham, M. Natural Gas Powered HVAC System for Commercial and Residential Buildings, ORNL/TM-2017/211, CRADA/NFE-16-016126.
Ally, M. R., “Technology 1: Solar Absorption Cooling System. Generate Desiccant Concentration up to 20 wt. percent. ORNL/Ltr-2018/1053, December 31, 2019.
Summary of outdoor air tests at various relative humidity and the 1st Law efficiency achieved by the BeCool System.
ORNL bench-top air handler with liquid desiccant flowing in three trays. The prototype air-handler dehumidifies humid outside air to reduce latent loads before it is supplied to the HVAC system.