GLOSSARY TERMS, CONTINUED
Gallons Per Minute A measurement of liquid flow. Indicates how many gallons of water that pass by a stationary point in one minute. Guest Room Energy Management Guest room energy management controls use sensors to determine when a room is unoccupied and adjust the HVAC system operations accordingly. When guests return, the system readjusts to meet guest comfort requirements. Heat Recovery Ventilator A device that captures the sensible heat from the exhaust air from a building and transfers it to the supply/fresh air entering the building to preheat the air and increase overall heating efficiency. Heating Seasonal Performance Factor A measurement of efficiency for heat pump equipment. For space heating seasons, HSPF is the ratio of total space heating delivered (in Btu) to the electrical input (in Watt-hours) if the heat pump operated exclusively in space heating only mode. High Turndown Burner A boiler burner mixes fuel with air to produce combustion. The turndown ratio is the maximum inlet fuel or firing rate divided by the minimum firing rate. A burner higher turndown ratio reduces burner starts, provides better load control, saves wear and tear on the burner, reduces refractory wear, reduces purge-air requirements, and provides fuel savings. Integrated Energy Efficiency Ratio A measure that expresses cooling part-load EER efficiency for commercial unitary air conditioning and heat pump equipment on the basis of weighted operation at various load capacities. IEER replaces IPLV for some equipment. Integrated Part-Load Value The efficiency performance factor at part- load cooling capacity. This performance is critical due to the higher quantity of operating hours under part-load conditions than at full load. Kilowatt-hours A unit of measurement for electrical energy usage. One kilowatt-hour equals 1000 watts of energy used for one hour. Kilowatts A unit of electrical power equivalent to 1000 watts.
Linkageless Controls Linkageless burner systems remove mechanical linkages and mod-motors and replace them with servomotors and microprocessors. These systems can better modulate O 2 , CO 2 , and CO to maximum efficiency across the firing rate. O 2 Trim Controls The oxygen trim system provides feedback to the burner controls to automatically minimize excess combustion air and optimize the air-to-fuel ratio. Outside Air Reset/Cutout Controls Automatic controls to adjust boiler water temperatures based on outside air temperature and actual space heating requirements. Packaged Terminal Air Conditioner Air conditioning units intended for mounting through the wall that have a wall sleeve and a separate unencased combination of heating and cooling assemblies. A PTAC includes refrigeration components, separable outdoor louvers, forced ventilation, and a heating system that may utilize hot water, steam or electric resistance. Packaged Terminal Heat Pump A type of PTAC that uses a reverse cycle refrigeration system for heating and includes a supplementary heat source. These units are more efficient than standard PTAC units. Pounds Per Square Inch Absolute A measurement of pressure. The force exerted on a surface in a fluid or gas measured relative to the absolute zero pressure – the pressure that would occur at absolute vacuum. Pounds Per Square Inch Gauge A measurement of pressure. The force exerted on a surface in a fluid or gas measured by a gauge relative to the surrounding atmosphere. Seasonal Energy Efficiency Ratio A measure of seasonal or annual efficiency of an air conditioner or heat pump. It takes into account the variations in temperature that can occur within a season and is the average number of BTU of cooling delivered for every watt-hour of electricity used by the heat pump over a cooling season.
Standard cubic feet per minute This measurement indicates how many cubic feet of air pass by a stationary point in one minute at standard conditions. Steam Trap Steam traps are automatic valves used in every steam system to remove condensate, air and other non-condensable gases while preventing or minimizing the passing of steam. If condensate is allowed to collect, it reduces the flow capacity of steam lines and the thermal capacity of heat A measure of the efficiency of converting a fuel to energy, heat or useful work. It is a ratio of energy output divided by fuel energy input expressed as a decimal or percentage (example: 0.95 or 95%). Variable Frequency Drive An electronic controller that adjusts the speed of an electric motor by modulating the power being delivered. Variable frequency drives provide continuous control, matching motor speed to the actual demands of the pump, fan or motor system. Motor speed fully modulates as the frequency of the alternating current is adjusted by the VFD. Variable Speed Drive transfer equipment. Thermal Efficiency Often used interchangeably with variable frequency drive. These drives are often used on smaller motors, direct current (DC) motors, and multiple speed motors that do not need full modulation.
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