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Cold Climate Heat Pumps Sizing - Problem Set 3.1

Source(s) or Contributor(s)
Pacific Northwest National Laboratory
Question
  1. What approach to sizing a ccASHP should be taken if the heat pump will be the only source of heat for the house?
    1. Size to meet most of the design heating load.
    2. Size to meet the design cooling load.
    3. Size to meet the design heating load.
    4. Size for cooling, but maximize available heating capacity.
  2. What approach to sizing a ccASHP should be taken if the homeowner wants to displace most, but not all, of the existing heating system’s output?
    1. Size to meet most of the design heating load.
    2. Size to meet the design cooling load.
    3. Size to meet the design heating load.
    4. Size for cooling, but maximize available heating capacity.

  3. When selecting a heat pump to meet most or all of the design heating load, what should a designer look for in terms of the unit’s cooling capacity?

    1. The unit’s maximum cooling capacity should be lower than the design cooling load.
    2. The unit’s minimum cooling capacity should be higher than the design cooling load.
    3. The unit’s minimum cooling capacity should be higher than the design heating load.
    4. The unit’s minimum cooling capacity should be lower than the design cooling load.
  4. What is the proper procedure for determining heat pump outputs at a temperature not given in performance tables?
    1. Perform a linear interpolation between two values greater and less than the desired temperature.
    2. Choose the output from the closest known temperature.
    3. Use data from a similar heat pump that specifies the desired temperature.
    4. Make a best guess based on available information.
  5. What are the effects of short cycling?
    1. Increased efficiency
    2. Increased occupant comfort
    3. Increased efficiency and occupant comfort
    4. Decreased efficiency and occupant comfort
  6. Why is it important to consider the latent cooling capacity when selecting a heat pump?
    1. Variable speed heat pumps sized for heating provide better dehumidification than traditional heat pumps.
    2. Summertime humidity is not an issue in cold climates
    3. Latent cooling capacity provides an indication of how well a unit dehumidifies in summer
    4. Heat pumps and air conditioners are not relied upon for dehumidification