Residential Dehumidification Systems Research for Hot-Humid Climates: September 1, 2001 -- December 30, 2003

Air-Source Integrated Heat Pump for Near-Zero Energy Houses: Technology Status Report

“…In this case "adequate" was taken to mean that indoor relative humidity (RH) levels would exceed 60% for no more than about 1 -2% of the year. The 60% criterion matches that used by Rudd et al (2005) in their study. Other studies use 65%, including a recent one by Witte and Henninger (2006) for ASHRAE that evaluated humidity control capability of various unitary system designs.…”

Initial Business Case Analysis of Two Integrated Heat Pump HVAC Systems for Near-Zero-Energy Homes

“…In this case adequate was taken to mean that indoor RH levels would exceed 60% for no more than about 1-2% of the year. The 60% criterion matches that used by Rudd, et al (2005) in their study. Other studies use 65% including a recent one by Witte and Henninger (2006) for ASHRAE that evaluated humidity control capability of various unitary system designs.…”

Development of an Integrated Residential Heating, Ventilation, Cooling, and Dehumidification System for Residences

“…(Christian, 2005 "While both houses were similar in size, total energy consumed for the Energyefficient Reference house was less than half that of the Standard Reference house. However, because of the reduced sensible heat gain, and the resultant reduction in cooling system operation, humidity control performance in the energy-efficient house was inferior" (Rudd et al, 2005) "Incorrect use of vapor barriers is leading to an increase in moisture-related problems." (Lstiburek, 2004) "Otherwise, in more humid regions of the Midwest and South, set up systems to operate at high latent capacities using indoor airflows in the 300 to 350 cfm per ton range."…”

“…However, because of the reduced sensible heat gain, and the resultant reduction in cooling system operation, humidity control performance in the energy-efficient house was inferior" (Rudd et al, 2005) "However, it has been noted that some houses built under this program (Building America) in the hot and humid climate and equipped with a dedicated ventilation system were reported to have longer periods of elevated interior relative humidity (RH>60%) relative to conventional houses without dedicated ventilation systems (Rudd 2003)" (Moyer et al, 2004) Conventional air conditioning systems are often not capable of effectively controlling indoor moisture, since the basic ability of the system to provide sensible (temperature reduction) and latent cooling (moisture removal) cannot be varied significantly. To efficiently provide comfort in these humid-climate energy-efficient homes, an integrated design approach capable of responding to varying indoor and outdoor conditions is needed.…”