Lecture Objectives: Finish with HVAC Systems Discuss Final Project

Building HVAC Systems (Primary and Secondary Building Systems) AHU – Air Handling Unit Distribution systems Fresh air For ventilation AHU Primary systems Air transport Electricity Secondary systems Cooling (chiller) Heating (boilers) Building envelope HVAC systems affect the energy efficiency of the building as much as the building envelope (or Gas) Gas

Integration of HVAC and building physics models Load System Plant model Building Qbuiolding Heating/Cooling System Q including Ventilation and Dehumidification Plant Integrated models Building Heating/Cooling System Plant

eQUEST HVAC Models Predefined configuration (no change) Divided according to the cooling and heating sources Details in e quest help file: For example: DX CoilsNo Heating Packaged Single Zone DX (no heating) Packaged single zone air conditioner with no heating capacity, typically with ductwork. Split System Single Zone DX (no heating) Central single zone air conditioner with no heating, typically with ductwork. System has indoor fan and cooling coil and remote compressor/condensing unit. Packaged Terminal AC (no heating) Packaged terminal air conditioning unit with no heating and no ductwork. Unit may be window or through-wall mounted. Packaged VAV (no heating) DX CoilsFurnace Packaged direct expansion cooling system with no heating capacity. System includes a variable volume, single duct fan/distribution system serving multiple zones each with it's own thermostatic control. Packaged Single Zone DX with Furnace Central packaged single zone air conditioner with combustion furnace, typically with ductwork. Split System Single Zone DX with Furnace Central single zone air conditioner with combustion furnace, typically with ductwork. System has indoor fan and cooling coil and remote compressor/condensing unit. Packaged Multizone with Furnace Packaged direct expansion cooling system with combustion furnace. System includes a constant volume fan/distribution system serving multiple zones, each with its own thermostat. Warm and cold air are mixed for each zone to meet thermostat control requirements.

Air-conditioning in Air Handling Unit (AHU) Roof top AHU Gas/Electric Heater to building Fan air from building fresh air Evaporator filter mixing AHU schematic Exhaust From room Return fan flow control dampers Supply fan Compressor and Condenser Fresh air To room Outdoor air hot water cool water

Processes in AHU presented in Psychrometric in psychrometric Case for Summer in Austin OA MA IA SA

Heat Recovery Systems Air to Air Heat Exchanger Plate heat exchangers Effectiveness ~50% Effectiveness ~75% Effectiveness ~60% Enthalpy wheel

Ventilation Heat Recovery Systems for cooling and heating Commercial buildings Residential buildings Saving % - depends on how much ventilation we have in the building

Water Cooled Chiller Task: analyze COP for the whole year Cooling tower Building Water 120°F Water 52°F Outside air 95°F Water 100°F Inside 75°F Water 42°F Task: analyze COP for the whole year and different locations

Solar hot water system

Geothermal Energy Systems (in combination with a cooling machine / heat pump) Summer Winter In the summer, the earth acts as a cooling tower. The Cooling Machine loads the loop with heat, sending warmed water to be cooled by the earth In the winter, the earth acts as the boiler. The Heat Pump extracts heat from the loop, sending cooled water to be warmed by the earth.