Condensers & Cooling Towers

Question 1

Wet bulb is actual temp felt, dry bulb is what’s measured on a __________

Answer 1

thermometer

Question 2

Cooling towers are heat ______. They do not condense refrigerant so they are not considered condensers

Answer 2

rejecters

Question 3

Plate Heat Exchanger Condensers:

1. ______ capacity design
2. not mechanically _______
3. also used as ________

Answer 3

smaller, cleanable, evaporators

Question 4

Fouling (Scaling Resistance)

1. Fouling is the build up of ______ on tube surfaces depends on the quality of water
2. Lower water velocities result in higher _______ rates

Answer 4

1. deposits

2. fouling

Question 5

Condenser Pass Arrangements:

One pass of tubing = low pressure drop ___ rise

Two pass of tubing = med pressure drop, ____ rise

Answer 5

1. low

2. medium

Question 6

Air Cooled Condensers:

1. No condenser water _____ and piping
2. Ease of ________

Answer 6

1. pump

2. maintenance

Question 7

Approximate Design Air-Cooled Condensing Temperature:

Design air inlet temp 95F
air rise 15F
leaving difference 15F

what is the refrigerant condensing temp?

Answer 7

125F

Question 8

Subcooling circuit:

1. ensures proper operation of liquid _______ device
2. Adds 0.5% to total system _______ per degree of sub cooling

Answer 8

1. metering

2. capacity

Question 9

In air conditioning an air in vs air out is just a range it is NOT a ___

Answer 9

TD

Question 10

Entering Wet Bulb Temperature:

1. entering wet bulb temp is the lowest temp that water can theoretically reach by _________
2. entering ___ bulb temp is the most important parameter in tower selection
3. For most areas in North ________ an entering wet bulb temp of 78F is common

Answer 10

1. evaporation
2. wet
3. America

Question 11

Cooling Tower Approach:

1. Approach is the difference between the water leaving the tower and the entering wet bulb temp of the ____
2. A 7F approach is common in HVAC systems with 78F entering wet bulb and 85F water leaving the _____

(85F - 78F = 7F)

Answer 11

1. air

2. tower

Question 12

Cooling Tower Range:

1. Range is the ________in the temp of water entering and leaving the tower
2. AN approx 9.4F - 10F range is most common in _____ applications

Answer 12

1. difference

2. HVAC

Question 13

Total Heat of Rejection:

1. This is the amount of heat to be ______ from the circulating water within the tower
2. It is equal to the refrigeration effect plus the work of _________
3. For water-cooled chillers (THR = (1.15 to 1.18) * cooling tons

Answer 13

1. removed

2. compression

Question 14

Drift (Windage)

1. Drift water that gets entrained in the airflow and discharged to the _______
2. Drift can vary widely and does not include water lost by _________
3. drift is very small and can usually be _______ in most calculations for make up
4. drift is approx 0.001 to 0.002% of the tower ppm

Answer 14

1. atmosphere
2. evaporation
3. neglected

Question 15

Evaporation:

1. For each pound of water that a cooling tower evaporates, it removes about 1050 btu from the _____ that remains
2. A lower entering wet bulb creates a ______ evaporator effect
3. Evaporation rate equals approx 1% of tower ___

Answer 15

1. water
2. greater
3. GPM

Question 16

Blow Down (Bleed Off)

1. Water contains impurities and when it is evaporated these _______ are left behind
2. If no action is taken the concentration of impurities will build up ______
3. Bleeding off some of the water is continuously required to _____ this build up

Answer 16

1. impurities
2. rapidly
3. limit

Question 17

Makeup:

Make up is the amount of water required to replace normal losses caused by ____, evaporation, and blow-down

Answer 17

drift

Question 18

Cooling Tower Fill:

1. Fill helps the water gain maximum exposure to the ______

Answer 18

1. airflow

Question 19

Induced-draft Crossflow-double inlet

1. Air passes through building on side horizontal to water flow

Answer 19

1. both

Question 20

Induced-draft Single inlet:

1. Induced draft with crossflow but only __ air inlet

Answer 20

1. one

Question 21

Forced - Draft Blow - Thru

1. Fan _____ air through tower
2. Uses centrifugal fans with ____ hp and _____ static pressure
3. High entrance ______
4. Applications would be HVAC ______

Answer 21

1. forces
2. high, high
3. velocity
4. hvac chillers

Question 22

Placement of Cooling Towers:

1. When selecting the location, sufficient clearance should be allowed for the ___ flow of air to the inlet of the tower. Insufficient clearance would necessitate a single inlet tower in this application
2. Obstructions will reduce airflow causing a reduction in _______
3. A 2F recirculation can equal up to a 19% reduction in _____

Answer 22

1. free
2. capacity
3. capacity

Question 23

Cooling Tower Discharge Concern:

1. Avoid placement where air discharge could cause _________ or wetting on nearby surface

Answer 23

1. condensation

Question 24

Where do fluids enter in a centrifugal compressor?

Answer 24

through the centre

Question 25

Effect of Reduced Cooling Tower Water Temperature:

As a rule of thumb, water-cooled equipment efficiency is increased approximately 2% for every _F decrease in entering condenser water temp

Answer 25

1F

Question 26

Water Treatment:

Problems a water treatment specialist can prevent: name 4. Acronym is SCSM

Answer 26

1. Scaling
2. Corrosion
3. Sludge
4. Micro-biological contamination