Integrated forced-air heating and ventilation systems: evaluation and design considerations.

Mechanical systems which use common ducts for combined heating and ventilating functions are becoming popular in the Pacific Northwest (U.S.). These systems range from simple fresh-air inlets ducted to the return side of a forced air heating s stem to more complex heat recovery ventilation systems utilizing the K eating ducts for air distribution. Typical integrated systems do not have heat recovery capability.

Warm air heating with a constant high supply air flow rate without recirculation.

In Halmstad a multi-apartment house has been built with air carried heating. Fresh air was used as the only heat carrier. To improve the air quality it was decided not to use circulation flow, which is normally required for air carried heating. Theheating requirement was obtained with a higher air flow than what the standard requires. This also implied improved air quality. The standard specification states 0.5 changes per hour as the minimum requirement, but in Halmstad the house was ventilated with 0.7 - 1.0 changes per hour.

Ventilation system as an air heating system - measuring results in a residential building.

This paper presents measuring results from experiments with integrated air heating and ventilation system in airtight well-insulated buildings in Stockholm (The Stockholm Project) .

Recirculation of air in dwellings. Differences in concentration between rooms in dwellings due to the ventilation system.

The Dutch Standard NEN 1087 "Ventilation of dwellings": Requirements (1) is at this moment under review. A requirement can be found about the quality of air. In fact a statement is made that outside air is required as fresh air for bedrooms. Bathroom, kitchen, W.C. and living-room are allowed to be ventilated with air from other rooms. During the last years air heating systems became more popular. These systems have,in its most simple form,recirculation of air from the living-room to the bedrooms.

Air heating systems in airtight multifamily residential buildings.

This paper presents an analysis of indoor climate in buildings with forced air heating systems. The results is based on indoor climate measurements and extensive interviews with the occupants. The analysis shows that design criteria is of great importance for the occupants conceptions of thermal comfort in buildings with air heating systems. Forced air heating systems could be a way to provide mechanical supply air with less problems with the thermal comfort, such as draught, than in ordinary supply- and exhaust air ventilation systems.