Chap 51
Total heat load represents the amount of heat that a commercial refrigeration system must remove in a(n) ____ period
What is 24 hour?
For a reciprocating compressor, the theoretical compressor volume is determined by the ____.
What is the # of cylinders , bore and stroke?
T or F
It is advisable to add 15%–20% to the calculated compressor load to ensure that the system components will not be undersized.
What is False?
The refrigerant velocity in the liquid line is typically between?
What is 100 fpm and 300fpm?
Name 2 types of metering devices?
What is Capillary Tube, TEV, EEV, and Txv
Once the relative humidity of the conditioned space is selected based on the product being refrigerated, the ____ can be determined.
what is temperature difference?
The heat transfer rate for forced-draft evaporators is approximately ____.
What is 3Btu/hr-ft?
The lower the number of fins per inch (FPI), the greater the ______ ______ of the evaporator.
What is the surface area?
Why should you install an inverted trap at the top of a vertical riser in a suction line?
What is to prevent oil from flowing back down the riser when system is not operating?
Name both kinds of capacitors?
What is start and run?
The saturated suction line temperature can be calculated by subtracting the temperature difference from the design temperature of the ____.
What is the conditioned space?
The heat transfer rate for natural-draft evaporators is approximately _____.
What is 1Btu/hr-ft?
The equivalent length for each fitting and valve in a line is added to the length of the line itself to find the line's ____.
What is total equivalent length?
Name the two things that affect pressure drop in refrigerant lines?
What is length and diameter?
Name 2 types of solenoids?
What is hot-gas and liquid line/pump down?
Air-cooled condensers in commercial systems generally have a temperature difference of ____
What is 10F-30F?
The required minimum velocity for a refrigerant line depends on the ____.
What is the temp of the refrigerant ,type of refrigerant and size of the line?
If refrigerant lines are too small, they create excessive what?
What is pressure drop?
The refrigerant line that should have a pressure drop of 0 psi and a velocity of 100 fpm or less is the _____ line.
What is the condenser condensate?
What is superheat?
What is the sensible heat added to a vapor above its Saturation?
The total heat load for a system plus the energy added to the refrigerant by the compressor is the ____
What is total heat of rejection?
For most refrigerant lines, the maximum allowable pressure drop is equal to a saturation temperature drop of ____.
What is 2degrees F?
T or F?
A smaller compressor with a longer operating cycle can be as effective as a larger compressor with a shorter operating cycle.
What is true?
Excessive pressure drop can cause _____ in a liquid line.
What is Flash Gas?
What does saturation mean?
What is both liquid and vapor are present ?
Liquid receivers should be sized ____ larger than the total liquid volume in a system.
What is 15%?
T or F
A smaller compressor with a longer operating cycle can be as effective as a larger compressor with a shorter operating cycle.
What is true?
The required capacity for the condenser is ______ ______the required capacity for the compressor.
What is greater than?
Liquid refrigerant migration from the condenser to the compressor is possible during the Off cycle when the ____.
What is the condenser is warmer than the compressor?
What is the first thing you should do before starting to troubleshoot a unit?
What is find the data plate ?