摘要或動機

1. Purpose: The purpose of this project was to design a theoretical tempered-air system to be integrated into an existing heating system in a home equipped with an air-to-air heat pump. This was to overcome the cost and environmental challenges of heating in cold climates as well as provide an environmentally friendly air-conditioning system in the summer at little to no cost. 2. Procedure: In the winter of 2010 an underground high-density polyethylene (HDPE) pipe (10cm diameter, and 30.5m length) was buried 2.5m underground around the footings of a new residential project. A fan with a flow of 3.4m³/min was attached to the pipe outside, and used to push air underground through the pipe and into the house. The ambient and incoming air temperatures as well as the date and time were recorded daily using a temperature probe with an error margin of ±0.1ºC throughout the summer and winter seasons of 2011. This data was then plotted and analyzed. A number of options to best extract thermal energy for potential use for heating and cooling were examined. Design components were selected to create an air chamber for an air-to-air heat pump to increase its coefficient of performance (COP). 3. Data: Graph 1 Graph 2 Winter Graph (Graph 1): The blue line represents the outdoor ambient temperature and the orange line represents the temperature of the tempered air. These are both arranged chronologically. The grey lines represent one standard deviation on either side of the incoming temperatures. The ambient temperatures vary dramatically, while the incoming temperatures remain quite stable. The lowest recorded temperature was about -9.0ºC, at which point the temperature exiting from the underground pipe was about 10.5ºC. Summer Graph (Graph 2): With dramatically varying ambient temperatures, the temperature of the incoming air consistently stays between 11.1 and 16.2ºC. The highest recorded outdoor temperature was about 30.0ºC, while the incoming temperature at that point was about 15.5ºC. This cold air was used as air conditioning.