Sensitivity of occupant comfort models to humidity and their effect on cooling energy use
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Residential building energy consumption in the United States has decreased steadily during the last several decades largely because of advances in building codes as well as voluntary efficiency and labeling programs, which have resulted in the reduction in building sensible loads. Building latent loads have not decreased by the same amount, and field and analytical research studies have concluded that high-efficiency, low-load homes often have elevated indoor humidity levels, possibly leading to occupant discomfort. There are discrepancies in the literature on occupant comfort as it relates to indoor humidity and recommended upper humidity limits. The choice of humidity limit could potentially change results and conclusions on the energy impacts of a new air conditioner or dehumidifier technology, changing ventilation rates, or an improved building envelope. In this study, we use building simulations to explore the impact of humidity control on cooling energy use in efficient residential buildings for different humidity limits. We look at limits based on humidity ratio (or dew point temperature), wet-bulb temperature, relative humidity, and constant slope lines based on the popular comfort models of both Fanger and Gagge. We quantify the additional energy use required to control humidity below these limits. We look at the sensitivity of the results to different temperature and humidity set points, occupant internal gains, moisture buffering levels, evaporator airflow rates, and dehumidifier energy factors. High-efficiency home predicted energy savings are more sensitive to the assumed humidity limit and cooling and dehumidification set points than the other parameters investigated in this paper.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); National Renewable Energy Lab. (NREL), Golden, CO (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE), Energy Efficiency Office. Building Technologies Office
- Grant/Contract Number:
- AC05-00OR22725; AC36-08GO28308
- OSTI ID:
- 1546543
- Alternate ID(s):
- OSTI ID: 1544530; OSTI ID: 1693480
- Report Number(s):
- NREL/JA-5500-73169
- Journal Information:
- Building and Environment, Vol. 162, Issue C; ISSN 0360-1323
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
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Related Subjects
Comfort models
Occupant comfort
Indoor humidity
Cooling energy
Low load
Moisture buffering
Effective moisture penetration depth
Humidity
Building energy modeling
Moisture
comfort models
occupant comfort
indoor humidity
cooling energy
low load
moisture buffering
effective moisture penetration depth
humidity
building energy modeling
moisture