ENVIRONMENTAL-CONDITIONS IN A GROWING-FINISHING SWINE BUILDING VENTILATED WITH AND WITHOUT EARTH TUBE HEAT-EXCHANGER

An earth tube heat exchanger was coupled with a slotted air inlet in t hree rooms of a growing-finishing swine building. A slotted air inlet provided fresh outside air to three other rooms without heating. Excha ngers 1, 2, and 3 consisted of three, four, and four pipes of 0.3 m di ameter non-perforated plastic drainage pipes, respectively. Each line was 61 m long and buried at 3 m depth. The air temperature, relative h umidity, and ventilation rate of each room were measured between Janua ry 18, 1990 and February 14, 1991. Growth performance and health of pi gs were also evaluated. For different combinations of outside air temp erature and pig mass, there was no significant effect of the exchanger on ventilation rate compared to the conventional system. Pneumonia le sions, atrophic rhinitis degrees, and growth performance of pigs were not affected by use of the exchanger. In this study, no difference was observed between the two ventilation systems. The construction and us e of similar earth tube heat exchanger is therefore not recommended in regions with equivalent energy costs and climatic conditions to that of Quebec.