An investigation of commercial building HVAC power density and energy consumption.

摘要

This project developed a set of HVAC (Heating, Ventilating, and Air Conditioning) power density guidelines in W/ft2 that will establish the acceptable allowances of power demand of the HVAC systems of commercial buildings. A user friendly energy calculator was also developed that will allow for the input of performance data for various HVAC mechanical systems with a comparison to the power density guidelines.;The power density guidelines developed were based on 20 types of commercial buildings and include allowances for the seven DOE suggested U.S. climate zones and three building efficiencies: Base, High, and Premier. Acceptable levels of thermal heat gains/losses for each of the building types were analyzed through load calculation software and based on the three levels of building efficiency and climate zones. These thermal gains/losses were then divided by an HVAC system Energy Efficiency Ratio (EER) of 10 Btu/W•hr for Base efficiency buildings, 11.5 Btu/•hr for High efficiency, and 13 Btu/W•hr for Premier efficiency. This provided the acceptable power density values and are tabulated in the appendices. An interactive spreadsheet program was developed to provide users easy access to the values of interest and determine the total heat gain/loss through the input of the floor area of an analyzed building.;The energy calculator utilizes five different HVAC system types and allows the user to input occupancy schedules, occupied/unoccupied thermal loads, and individual equipment operating perimeters to determine the electrical consumption (kWh/year), natural gas consumption (Therms/year), and corresponding costs based on user defined inputs for utility rate charges. The results of each of the five system types can then be compared and adjusted to lower energy consumption and/or operating costs.;The results of four different energy studies were analyzed by the power density and energy calculator programs and it was found that the energy consumption and demand of current buildings is highly erratic with levels significantly greater than those recommend by the programs. Graphically represented results are included that compare the analytical to the empirical data. It is suggested that independent metering of building HVAC systems is needed to better establish the relationship between power (demand) and energy densities.