Residential building energy use and HVAC system comparison study

The objective of this study was to evaluate alternative heating and cooling approaches for a non-typical residence including geothermal and radiant floor heating technology. The analysis included four main components: estimating the design heating and cooling loads of the home, developing alternative approaches for heating and cooling the residence, designing an hourly energy use and heating, ventilating, and air conditioning (HVAC) system performance simulation model for the home over a period of one year, and estimating economic factors for each alternative system. Four alternative approaches for conditioning the case study home were developed and evaluated. These alternatives include systems that utilize either a water-to-air ground-source geothermal heat pump or a liquid-propane gas furnace for the forced air conditioning and either an electric boiler, liquid propane boiler, or a water-to-water ground-source geothermal heat pump for hydronic heating. Using the design heating and cooling loads on the home, specific equipment for each alternative was selected. The hourly energy demand on the home was simulated considering conduction heat transfer through the structure, solar loads, infiltration effects, and internal gain. The HVAC system model estimates the hourly performance of each alternative system given the hourly demand on the home. In addition, the approximate monthly and annual costs associated with each system were determined. Typical Meteorological Year (TMY2) data was used to estimate hourly weather and solar conditions expected at the geographical location of the home over a one year period. The economics for each alternative approach was evaluated based on a life-cycle-cost analysis. All annual expenses and savings for each approach were estimated over the assumed life of each system. The present-value and payback-period for each system was determined and compared. It was found that the approach utilizing a ground-source geothermal heat pump and electric hydronic boiler would be the most economical