Mao - Mecanical Systems

Front 1

Refridgeration Cycle

Back 1

- Freon
- Compressor
- Evaporator
- Condenser
See video for further info

Front 2

Efficiency vs COP

Back 2

- Efficiency = energy delivered / energy used
- COP (Coefficient of perfomance = energy delivered / energy used
- takes into account heat delivered from the outside

Front 3

Types of distribution

Back 3

Electrical, hydronic, and forced air

Front 4

Electrical distrubution

Back 4

- cheapest initial, most expensive life cycle
- radiant systems
- baseboard heaters - cause convective air circulation

Front 5

Hydronic distribution

Back 5

- typically radiant systems
- single pipe, only one pipe
- two pipe, separate supply and return
- four pipe, separate heating and cooling registers
- three pipe, four pipe but sharing return pipe

Front 6

Forced Air distribution

Back 6

- Single Duct, constant volume, air controlled by a damper, can have optional reheat system
- Double Duct, heat and cool simultaneously, controlled at each room by damper and mixing box
- Multi-zone system, similar to dual duct but the mixing boxes are in equip room
- Fan Coil system, constant volume of air sent to each room over chilled water or hot water coils
- Variable Air Volume, can't heat and cool simultaneously within same zone, but can across zones

Front 7

Unitary system

Back 7

air directly from outside thru unit into room

Front 8

Heat Pump System

Back 8

- group of heat pumps serving a building
- water circulated thru building called heat sink
- each zone has own heat pump and fan

- delivers more energy than the energy required to run the pump

Front 9

Filter types

Back 9

- Fibrous - similar to home furnace filter, remove duct/lint, replace regularly
- Electrostatic - more expensive, less resistance to air, two charged plates that attract dust
- Activated charcoal - removes odors and chemicals, lots of resistance to air flow, change regularly

Front 10

Duct Sizing

Back 10

A = 144Qcfm / v where
Qcfm = qtot / 1.08(Teq - Ti)
A = are of duct
v = velocity in feet per minute
qtot = total thermal load in Btuh
Teq = temp of air supplied in duct (55 for cooling and 140 for heating)
Ti = desired interior temp for room

Front 11

Static Head

Back 11

- One inch fo static head is the pressure require to support a one inch column of water (normal atmospheric pressure would support a 33-foot column of water)

Front 12

Can provide simultaneous heating and cooling to different rooms w/in same zone

Back 12

- Single Duct constant volume w/ electric reheat system

- Double duct system

- Fan coil system