REF UNIT 22

Question 1

what are the end caps of the shell of tube and shell condensers called?

Answer 1

water boxes (that’s where water circulates)

Question 2

what is the typical flow rate in a wastewater system with 75F entering water?

Answer 2

1.5 GPM/ton

Question 3

what is the typical flow rate in a recirculating water system with a cooling tower?

Answer 3

3 GPM/ton

Question 4

what valve controls water flow rate in wastewater system?

Answer 4

water-regulating valve

Question 5

what is the typical DTD Inca recirculated water system?

Answer 5

about 10F

Question 6

(12.1) why are condensers sized at 15,000 BTU/ton?

Answer 6

because the condenser has to reject extra heat caused by HOC.

Question 7

(22.4) can coiled tube-in-tube condenser’s be mechanically cleaned?

Answer 7

no

Question 8

(22.6) how does a shell-and-coil condenser work?

Answer 8

refrigerant is in the shell, water flows through coil inside shell.

Question 9

(22.7) can you mechanically clean a shell-and-tube condenser?

Answer 9

yes.

Question 10

(22.8) a standard cooling tower can only cool water within ___ to ___ degrees of the ambient wet bulb temperature.

Answer 10

7 to 8.

Question 11

(22.11) what are the 3 different types of cooling towers?

Answer 11

natural draft, forced draft, evaporative.

Question 12

(22.12) define makeup water

Answer 12

water added to cooling tower to make up for evaporated water.

Question 13

(22.14) how are evaporative condensers different from cooling towers?

Answer 13

evaporative condensers are inside the cooling tower, and other condensers are outside of the cooling tower.

Question 14

(22.14) define blowdown

Answer 14

the water dumped by a cooling tower to prevent mineral deposits.

Question 15

(22.18) what does flooding the compressor accomplish?

Answer 15

raises head pressure under low ambient conditions.

Question 16

(22.18) what is a LAC valve?

Answer 16

low ambient control valve. Floods the condenser under low ambient conditions.

Question 17

(22.18) if all the refrigerant in a system is pumped into the receiver, how full should that receiver be?

Answer 17

80%

Question 18

(22.18) what does splitting the condenser accomplish?

Answer 18

reduces the amount of extra refrigerant charge needed for changing outdoor conditions.

Question 19

(22.21) what does floating head pressure mean?

Answer 19

letting the head pressure fluctuate with ambient temperature for lower compression ratios for better efficiency.