tight house

Mr.Platts briefly reviews current Canadian housing and the potential for controlled ventilation with exhaust air heat recovery. Discusses cost effectiveness of exhaust air heat recovery and suggests that payback periods are generally too long and hence uneconomic. Mr.Bonnyman discusses the market for domestic heat recovery units. Briefly reviews the types of heat recovery equipment. Gives product information for units available in Canada.

Measurements of air change rates, carbon dioxide concentrations, room air temperatures and relative room air humidities in bedrooms of five well tightened dwellings were carried out in October 1989. With the results of the measurements and also based on simulation calculations, recommendations for an optimal window opening behaviour in bedrooms with the intention of saving energy and of providing sufficient indoor air quality were made.

The climatical conditions in Sweden are such that it has almost always been necessary to tighten the houses quite thoroughly in order to avoid cold-draught and to make as good use of the heating as possible. Devices for intentional ventilation, such as ducts for the exhaust of "used" air, have been installed in Swedish houses for centuries. Thus the concept of infiltration and ventilation is not a new one. The more general introduction of central heating in the beginning of this century led to a relatively high degree of dependance on imported fuel.

This work is concerned with measuring air flows between the floors of houses. A simple measuring technique is described in which two portable SF6 systems were employed. The design and construction of the portable system are presented. A comparison of air flow patterns in a superinsulated house and a standard house is made. Results showed that the air flow between the upper and lower floors of the superinsulated house was about 20 m3/h compared with 100 m3/h in the traditionally built house.

Three balanced airflow ventilation devices were evaluated, an exhaust and supply fan (E&SF), air-to-air heat exchanger (ATAHE), and exhaust air heat pump (EAHP), which can be used to increase the ventilation rate in an R-2000 (tightly constructed) type house. A prototype of the EAHP, which uses a combination of heat pipe and heat pump, was built and tested. A frosting and non-frosting version of the EAHP were evaluated. The non frosting version provided the best overall performance.

This report examines three devices (exhaust fan, air-to-air heat exchanger and exhaust air heat recovery heat pump) which could be used to increase the ventilation rate of a tightly constructed house to a level sufficient to keep indoor air pollutants and moisture to acceptable concentrations.