RSES System Design & Load Calculation 3

Question 1

What does the 'system balance point' mean in refrigeration system design?

Accepted Answer

The operating condition where system capacity exactly matches the refrigeration load

Answer

The point at which the compressor oil pressure equals suction pressure

Answer

The electrical balance between phase voltages on a three-phase system

Answer

The midpoint between high-side and low-side pressures

Question 2

Short cycling in a refrigeration system is most likely to result in which design problem?

Accepted Answer

A grossly oversized system that satisfies the load too quickly without adequate run time

Answer

Inadequate insulation thickness causing excessive transmission load

Answer

Undersized condensing unit that cannot meet peak demand

Answer

Incorrect refrigerant charge causing insufficient evaporator flooding

Question 3

When performing a refrigeration load calculation, what does the 'sensible heat ratio' (SHR) indicate?

Accepted Answer

The proportion of the total cooling load that is sensible (temperature-changing) versus latent (moisture-removing)

Answer

The ratio of compressor sensible heat rejection to total condenser heat rejection

Answer

The ratio of indoor air temperature to outdoor design temperature

Answer

The ratio of suction pressure to discharge pressure in the system

Question 4

In a refrigerated display case load calculation, what is the 'radiation load' component?

Accepted Answer

Heat transferred from warm surrounding objects and customers via infrared radiation to the open case

Answer

Heat emitted by the refrigerant as it absorbs heat from the product

Answer

Electrical energy consumed by the evaporator defrost heaters

Answer

Heat generated by the compressor motor during operation

Question 5

What impact does increasing the evaporator TD (temperature difference) have on relative humidity inside a refrigerated space?

Accepted Answer

It decreases relative humidity because the colder coil aggressively removes moisture from the air

Answer

It increases relative humidity by preventing moisture condensation

Answer

It has no effect on relative humidity in the space

Answer

It increases relative humidity by reducing refrigerant flow

Question 6

When sizing refrigeration equipment, what is the purpose of accounting for 'motor heat' from evaporator fan motors?

Accepted Answer

To include the heat added to the refrigerated space by fan motor electrical energy converted to heat

Answer

To determine the correct motor amperage for the electrical panel

Answer

To ensure the motors are rated for the ambient temperature

Answer

To select fan blades that rotate at the correct speed

Question 7

What is the primary reason for calculating a separate 'pull-down load' distinct from the steady-state storage load?

Accepted Answer

The system may need significantly more capacity during the initial temperature reduction than it does for steady-state maintenance

Answer

Pull-down load determines the minimum pipe diameter required for the suction line

Answer

Pull-down load sets the maximum allowable refrigerant charge for the system

Answer

It is required by EPA regulations for all commercial systems above 5 tons