1. Lecture Objectives:
Finish with HVAC Systems
Discuss Final Project

2. 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

3. 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

4. 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.

5. 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

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

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

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

9. 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

10. Solar hot water system

11. 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.