lecture objectives: finish with hvac systems discuss final project
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Lecture Objectives:
• Finish with HVAC Systems
• Discuss Final Project
Building HVAC Systems (Primary and Secondary Building Systems)
AHU
Buildingenvelope
Cooling(chiller)
(or Gas)
Electricity
Gas
Heating(boilers)
Fresh air For ventilation
Distribution systems
Air transport
Secondary systems
Primarysystems
AHU – Air Handling Unit
HVAC systems affect the energy efficiency of the building as much as the building envelope
Integration of HVAC and building physics models
BuildingHeating/Cooling
SystemPlant
BuildingHeating/Cooling
SystemPlant
Load System Plant model
Integrated models
Qbuiolding Q
including
Ventilation
and
Dehumidification
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)
Compressorand Condenser
Roof top AHU
Gas/Electric Heater
to building
Fan
air from building
fresh air
Evaporator
filtermixing
hotwatercool
water
Return fan
Supply fan
flow control dampers
AHU
Fresh air
AHU schematic
Outdoor air To room
Exhaust From room
Processes in AHU presented in Psychrometric in psychrometric
OA Case forSummer in Austin
IA
MA
SA
Heat Recovery SystemsAir to Air Heat Exchanger
Plate heat exchangers
Enthalpy wheel Effectiveness ~60%
Effectiveness ~75%
Effectiveness ~50%
Ventilation Heat Recovery Systemsfor cooling and heating
Commercial buildings Residential buildings
Saving % - depends on how much ventilation we have in the building
Water Cooled Chiller
Outside air 95°F
Inside 75°FWater 42°F
BuildingWater 52°FWater 120°F
Water 100°F
Cooling tower
Chiller
Task: analyze COP for the whole yearand 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.
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