144. Adjusting flow in a two pipe secondary coolant system may be difficult because

a. brine solution has a high specific gravity

b. of load variation

c. of evaporator size variation

d. of short circuiting

d. of short circuiting 8-9

145. The three pipe brine system is considered balanced because

a. the evaps are the same size

b. resistance to flow is fairly equal in all circuits

c. the pipe size is the same

d. it has restricting valves

b. resistance to flow is fairly equal in all circuits 8-9

146. How is change of state affected when a quantity of salt is added to water that results in a 10% solution?

a. the freezing temp is lowered

b. the specific gravity is decreased

c. the freezing temp is increased

d. there is no effect

b. the specific gravity is decreased 8-3

147. All glycol based solutions can be classified as

a. secondary coolants

b. non-toxic

c. corrosive

d. brines

a. secondary coolants 8-3

148. What is the approximate freeze point of a 20% solution of calcium chlorize?

a. 10F

b. 0F

c. -10F

d. -20F

b. 0F 8-4

149. What is the eutectic point of a brine solution?

a. the lowest temp at which a mixture freezes

b. the temp at which liquid, solid, and gas can all exist.

c. the temp at which a brine isused

d. the flow rate at which a brine becomes turbulent

a. the lowest temp at which a mixture freezes 8-4

150. What are the two greatest advantages of secondary coolant systems?

a. secondary coolants are always non-toxic and reduce the cost of providing refrigeration

b. secondary coolant systems are more efficient than DX evaps and can reduce the primary refrigerant charge

c. Secondary coolants have the ability to store refrigeration and can reduce the primary refrigerant charge

d. Secondary coolants work well in making ice cream and do not frost.

c. Secondary coolants have the ability to store refrigeration and can reduce the primary refrigerant charge 8-2, 3

151. The eutectic point for sodium chloride is

a. -67F/29.87%

b. -59.9F/ 60%

c. -54.9F/ 60%

d. -5.1F/ 23%

d. -5.1F/ 23% 8-4

152. What brine distribution problem can exist in two pipe system?

a. Too low of a temp

b. circuit flow imbalance

c. overflow from the closed cooler

d. overflow of the balance tank

b. circuit flow imbalance 8-9

153. What is the most practical way to correct two pipe distribution system problems?

a. decrease the temp of the coolant

b. change the concentration of the coolant

c. increase the pump speed

d. manually balance the flow to each circuit by adjusting the restricting valves

d. manually balance the flow to each circuit by adjusting the restricting valves 8-9

154. Which of the following statements is not true regrading the balance line effect in three pipe systems?

a. all the circuits have the same resistance to flow

b. static head is canceled

c. reduced operating costs

d. increased required pump head

d. increased required pump head 8-9

155. A balance tank does all but one of the these in a three pipe system.  Which is it?

a. vents air from the return line

b. equalizes static head

c. allows for expansion and contraction of the brine solution

d. store cooled refrigerant to reduce the cooling load.

d. store cooled refrigerant to reduce the cooling load. 8-9

156. How is a secondary coolant typically heated for defrosting?

a. by shutting the expansion valve to the evap cooling the brine

b. by warming brine in a heat exchanger and delivering it to the unit to be defrosted.

c. with electrical heaters mounted on the cooling coils

d. the cooler is bypassed and the brine warms from room temp

b. by warming brine in a heat exchanger and delivering it to the unit to be defrosted. 8-11

157. Which is not a major component used in a two pipe secondary coolant system?

a. coolant pump

b. balance tank

c. expansion tank

d. cooling coils

b. balance tank 8-7

158. How can corrosion be controlled in a brine system?

a. Corrosion doesn't occur in brine systems

b. proper use of corrosion inhibitors along with regular monitoring of brine pH

c. by building the system using galvanized steel components

d. by using brass fittings.

b. proper use of corrosion inhibitors along with regular monitoring of brine pH 8-6