Cooling Coil - Water to Air Heat Pump

Coil:Heating:WaterToAirHeatPump:EquationFit

Used in:   Zone Water To Air Heat Pump Unitary Water To Air Heat Pump AHU

The Water to Air Heat Pump Cooling Coil uses a simple curve-fit model that requires coefficients generated from heat pump catalogue data. This is an equation-fit model that resembles a black box with no usage of heat transfer equations. The performance of the heat pump is modelled using curves fitted from the catalogue data. A detailed description of the equation-fit model is available in the following reference: Tang,C. C. 2005. Modeling Packaged Heat Pumps in Quasi-Steady State Energy Simulation Program. M.S. Thesis. Department of Mechanical and Aerospace Engineering, Oklahoma State University. It is also downloadable from www.hvac.okstate.edu.

General

Name

A unique auto-assigned name identifying name for the coil. Any reference to this coil by another object (typically a Zone Water To Air Heat Pump) will use this name.

Rated air flow rate

This numeric field contains the rated volumetric air flow rate on the load side of the heat pump (in m3/s or ft3). This field is autosizable.

Rated water flow rate

This numeric field contains the rated volumetric water flow rate on the source side of the heat pump (in m3/s or gal/min). This field is autosizable.

Gross rated total cooling capacity

This numeric field contains the gross rated total cooling capacity of the heat pump (in W or Btu/hr). This field is autosizable.The gross rated total cooling capacity should be within 20% of the gross rated heating capacity, otherwise a warning message is issued. The gross rated total cooling capacity shouldnot account for the effect of supply air fan heat.

Gross rated sensible cooling capacity

This numeric field contains the gross rated sensible capacity of the heat pump (in W or Btu/hr). This field is autosizable. The gross rated sensible cooling capacity shouldnot account for the effect of supply air fan heat.

Rated cooling coefficient of performance

This numeric field contains the rated cooling coefficient of performance of the heat pump.

Total Cooling Capacity Coefficient 1 to 5

These numeric fields contain the first to fifth coefficient for the heat pump total cooling capacity.

Sensible Cooling Capacity Coefficient 1 to 6

These numeric fields contain the first to sixth coefficient for the heat pump sensible cooling capacity.

Cooling Compressor Power Consumption Coefficient 1 to 5

These numeric fields contain the first to fifth coefficient for the heat pump power consumption.

Others

Nominal time for condensate removal to begin

This numeric field defines the nominal time (in seconds) after startup for condensate to begin leaving the coil’s condensate drain line at the coil’s rated airflow and temperature conditions, starting with a dry coil. Nominal time is equal to the ratio of the energy of the coil’s maximum condensate holding capacity (J) to the coil’s steady-state latent capacity (W). Suggested value is 1000; zero value means the latent degradation model is disabled. The default value for this field is zero.

Ratio of initial moisture evaporation rate and steady state latent capacity

This numeric field defines ratio of the initial moisture evaporation rate from the cooling coil (when the compressor first turns off, in Watts) and the coil’s steady-state latent capacity (Watts) at rated airflow and temperature conditions. Suggested value is 1.5; zero value means the latent degradation model is disabled. The default value for this field is zero.