Sustainable Building Technical Manual - Etn-presco.net

. ☛ SUGGESTED PRACTICES AND CHECKLISTIHVACOperation Schedules❑ Adjust operating hours of heating and cooling systems to levels appropriate fortime of year, type of use, and occupancy patterns of the facility.❑ Adjust operating hours of ventilation systems according to potential contaminantlevels and the need to balance exhaust air.❑ Use timing devices to operate exhaust fans only when needed; coordinate withsupply fans and building pressurization requirements.❑ Use programmable thermostats to schedule and establish heating setpoints forvarious building occupancy patterns.❑ Schedule, control, and document ventilation rates to meet levels prescribed byASHRAE Standard 62-1989 for type of facility, occupancy lead time, and load.❑ Use building-control systems to operate HVAC equipment based on need, minimizesimultaneous heating and cooling, and supply thermal conditioning fromthe most efficient sources.– Set automatic temperature control based on pre-established ranges.– Use time-of-day and occupancy-based controls.– Supply air-temperature reset control for VAV systems.– Supply hot- and chilled-water temperature reset controls based on outside-air temperatureand hot- or chilled-water demand.– Use economizer control system to bring in outside air for cooling.Adjustment Control❑ Adjust space temperature and humidity setpoints to minimize space-conditioningrequirements.Do not set these limits below the lowest heating temperature—or above the highestcooling temperature—required to satisfy occupants’ needs, in accordance with thethermal requirements of ASHRAE Standard 55-1992.❑ Lower humidification and raise dehumidification setpoints based on time of year,occupant-generated moisture, and equipment- or material-protection needs, suchas those required by wood finishes and electronic components.System-Efficiency Improvements❑ Install air-to-air heat exchangers, which preheat cold outdoor supply air by transferringheat from warm exhaust air.❑ Install air-cleaning devices, such as particulate filters, activated carbon, electronicair cleaners, and other mechanisms that clean recirculated air.❑ Improve chiller efficiency.– Clean evaporator and condenser surfaces to maintain their heat-transfer capabilities.– Treat circulating water in cooling towers with chemical filtering to control scale,algae, and other deposits.– Implement control strategies that raise evaporator or lower condenser water temperaturesto reduce the differential between them.– Install evaporation-cooled or water-cooled condensers rather than replacing aircooledevaporators.❑ Improve boiler or furnace efficiency.– Properly adjust fuel-air ratios by installing flue-gas analyzers.– Reduce cooling effect of combustion air and cut energy consumption by preheatingcombustion air and reclaiming waste heat from feed water and fuel oil.