Performance and Impact from Duct Repair and Ventilation Modifications of Two Newly Constructed Manufactured Houses Located in a Hot and Humid Climate

摘要

Two nearly identical houses situated next to eachother in Bossier City, Louisiana were studied in aneffort to better understand moisture and coolingenergy related problems in manufactured houses withlow thermostat set-points during the cooling season.By design, the major difference between houses wasthe type of air conditioning units. House A had astandard split air conditioner and House B had a twospeedsplit air conditioner.In an effort to make the buildings more similar,the building airtightness was adjusted until it was thesame in each house, and duct leaks were sealed sothat the ducts were tight and there was equal tightnessin both houses. A ventilation system was also addedat the same time of duct repair. Duct repair and theventilation modifications resulted in significantimpacts on the cooling energy, temperature, relativehumidity, and building pressures. Cooling energydecreased 37% in House A and 18% in House B,while the floor space dewpoint increasedsignificantly. It is estimated that 35 % savings wasdue solely to duct repair in House A and 17% inHouse B. The primary cause of House A savingsbeing twice House B is attributed to House Aoperating at nearly twice the capacity most of thetime and had more duct leakage repaired. Thisresulted in higher system pressures and thereforegreater duct leakage than in House B. Beforebuilding modifications, House A used 15.4 kWh perday (32%) more than House B and 3.4 kWh per day(11%) more after modifications.A method of characterizing interstitial spacesusing dewpoint measurement is presented and showsthat the belly space became 2.6 times more likeoutdoor conditions after repairs in House A and 2.0times more in House B.