Heating Sources and Refrigeration Flashcards

1
Q

Natural gas is

A

Most common

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2
Q

Electricity is

A

Most expensive

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3
Q

Fuel oil/diesel may be used

A

in rural locations and is more common outside US

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4
Q

Liquefied Petroleum (LP)

A

may be used in rural locations

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5
Q

Steam

A

used in some urban areas (and on Cornell campus by Statler Hotel)

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6
Q

Centralized for heating

A

for heating, use a boiler to produce hot water and sometimes steam

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7
Q

Heat exchange or heat transfer

A

when two objects (typically liquid) come near each other and exchange heat

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8
Q

Centralized for chilled water

A

supplies cold water for water-based centralized HVAC systems

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9
Q

Secondary water

A

water used for heating and cooling
-chilled water supply and return
-condenser water supply and return

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10
Q

Refrigeration or vapour compression cycle

A

a circulating refrigerant removes heat from one location and transfers this heat to another location where it is rejected

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11
Q

Heat removal occurs in

A

the evaporator

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12
Q

Heat is rejected in

A

the condenser

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13
Q

The compressor provides

A

the energy necessary to accomplish this heat transfer

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14
Q

The expansion valve controls

A

the flow of refrigerant through the system

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15
Q

Chillers (and all refrigeration equipment) rely on the

A

refrigeration cycle

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16
Q

Refrigeration components

A
  1. expansion valve (controls flow of refrigerant)
  2. evaporator (liquid to vapour – super cools)
  3. compressor (vapour to compressed to hot, high pressure gas)
  4. condenser (vapour to liquid, hot gas cooled –condenses into liquid state)
17
Q

Expansion valve/metering device

A

controls the flow of the refrigerant into the evaporator

18
Q

Evaporator

A

refrigerant expands (to fill the space), boils, and evaporates
-refrigerant becomes very cold (below 0ºF) and is now able to absorb heat from space (air or water) you want to cool
-the refrigerant gets warmer and returns to the compressor

19
Q

Compressor

A

refrigerant gas is compressed into a hot, high-pressure gas (around 125ºF)

20
Q

Condenser

A

compressed gas travels to the condenser where it is cooled by either water or an air fan
-as it cools, it condenses into a liquid state
-refrigerant is now warm, high-pressure liquid (around 110ºF) leaving condenser

21
Q

Lower pressure is

A

easier to boil

22
Q

Higher pressure is

A

harder to boil

23
Q

CFC. Chlorofluorocarbons. (“Freon”)

A

-often hear of R-11, R-12
-very detrimental to the ozone (at 100%)
-Montreal accords. Can no longer be produced. Phased out
of usage in new equipment. (But it is still being used)

24
Q

HCFCs. Hydrochlorofluorocarbons

A

-often hear of R-22
-somewhat detrimental to the ozone (at around 5%)
-slated for phaseout by 2020

25
HFCs. Hydrofluorocarbons
no ozone impact
26
Other "refrigerants"
Ammonia, sulfur dioxide, carbon dioxide, methane “Recharge” or Refill refrigerants
27
Cooling tower
equipment that transfers waste heat into the atmosphere -supply cooled water to the condenser in the Chiller
28
Cooling tower fill
Forces the hot condenser water (return) to mix with air, promoting evaporation, which cools the condenser water
29
Cooling towers are large consumers of water because of the
evaporation and "blowdown" loss