Type 3254

This Type has two main purposes: estimating the performances from the environmental conditions and the compressor frequency, and to deter­mine the supply air state. The capacity output can be controlled through the frequency input. Moreover, the Type 3254 is able to operate in heating and cooling mode, and to simulate defrost cycles. For more details, have a look at the in-depth features section.

Inputs

1. Inlet (return) air temperaturereal

The dry-bulb temperature of the air entering the indoor unit of the heat pump. This air is typically at room air conditions.

2. Inlet (return) air humidity ratioreal \(\geq 0\)

The absolute humidity ratio of the air entering the indoor unit of the heat pump. This air is typically at room air conditions.

This input is not considered if parameter 1 is set to 2.

3. Inlet (return) air relative humidityreal \(\in [0, 100]\)

The percent relative humidity of the air entering the indoor unit of the heat pump. This air is typically at room air conditions.

This input is not considered if parameter 1 is set to 4.

4. Inlet (return) air pressurereal \(\geq 0\)

The absolute pressure of the air entering the indoor unit of the heat pump. This air is typically at room air conditions.

5. Inlet (return) air mass flow ratereal \(\geq 0\)

The air flow rate entering the indoor unit of the heat pump.

6. Outdoor air dry bulb temperaturereal \(\in [0, 100]\)

The dry-bulb temperature of the air entering the outdoor unit of the heat pump.

7. Outdoor air humidity ratioreal \(\geq 0\)

The absolute humidity ratio of the air entering the outdoor unit of the heat pump.

8. Outdoor air relative humidityreal \(\in [0, 100]\)

The percent relative humidity of the air entering the outdoor unit of the heat pump.

9. Outdoor air pressurereal \(\geq 0\)

The absolute pressure of the air entering the outdoor unit of the heat pump.

10. Normalized compressor frequencyreal \(\geq 0\)

The frequency of the compressor, normalized by its rated value (parameters 7 and 8).

11. Indoor unit fan speed ratioreal

The indoor unit fan speed, normalized by its rated value. It is also the value of the normalized air flow rate. If negative, the return air mass flow rate input will be used instead.

12. Operating modeinteger \(\in \{0, 1\}\)

Setting for heating/cooling mode:

\(0\)

cooling mode

\(1\)

heating mode
13. Defrost modeinteger \(\in \{0, 1, 2\}\)

Setting for defrost mode:

\(0\)

Set to defrost mode

\(1\)

Set to recovery mode

\(2\)

Set to steady-state mode
14. Recovery penaltyreal \(\in [0, 1]\)

Correction factor for the heating capacity when the heat pump operates in recovery mode. See recovery penalty.

Parameters

1. Humidity inputs modeinteger \(\in \{2, 4\}\)

This parameter indicates which input to this model will be used for the moist air calculations:

\(2\)

Percent relative humidity (input 3)

\(4\)

Humidity ratio (input 2)
2. Rated total cooling powerreal \(\geq 0\)

The input power of the heat pump at its rated conditions in cooling mode.

3. Rated cooling capacityreal \(\geq 0\)

The cooling capacity of the heat pump at its rated conditions.

4. Rated total heating powerreal \(\geq 0\)

The input power of the heat pump at its rated conditions in heating mode.

5. Rated heating capacityreal \(\geq 0\)

The heating capacity of the heat pump at its rated conditions.

6. Rated inlet air flow ratereal \(\geq 0\)

The rated value of the air volumetric flow rate entering the indoor unit of the heat pump.

7. Rated cooling frequencyreal \(\geq 0\)

The rated frequency of the heat pump compressor when operating in cooling mode.

8. Rated heating frequencyreal \(\geq 0\)

The rated frequency of the heat pump compressor when operating in heating mode.

9. Indoor fan rated powerreal \(\geq 0\)

The rated power of the indoor unit fan.

10. Outdoor fan rated powerreal \(\geq 0\)

The rated power of the outdoor unit fan.

11. Backup heater capacityreal

The capacity of the backup heater that is used when the heat pump cannot work due to extreme conditions. If the value is negative, the same value as the heating rated capacity will be used.

12. Logical Unit - cooling modeinteger \(\geq 10\)

The logical unit which will be assigned to the data file which contains the heat pump cooling performance data.

13. Logical Unit - heating modeinteger \(\geq 10\)

The logical unit which will be assigned to the data file which contains the heat pump heating performance data.

Outputs

1. Outlet (supply) air temperaturereal

The dry-bulb temperature of the air exiting the indoor unit of the heat pump.

2. Outlet (supply) air humidity ratioreal \(\geq 0\)

The absolute humidity ratio of the air exiting the indoor unit of the heat pump.

3. Outlet (supply) air relative humidityreal \(\in [0, 100]\)

The percent relative humidity of the air exiting the indoor unit of the heat pump.

4. Outlet (supply) air pressurereal \(\geq 0\)

The absolute air pressure of the air exiting the indoor unit of the heat pump.

5. Outlet (supply) air mass flow ratereal \(\geq 0\)

The flow rate of dry air exiting the indoor unit of the heat pump.

6. Total cooling ratereal \(\geq 0\)

The rate at which heat (both sensible and latent) is removed from the conditioned air stream in cooling mode.

7. Sensible cooling ratereal \(\geq 0\)

The rate at which sensible heat is removed from the conditioned air stream in cooling mode.

8. Latent cooling ratereal \(\geq 0\)

The rate at which latent heat is removed from the conditioned air stream in cooling mode.

9. Heat rejection ratereal \(\geq 0\)

The rate at which heat is rejected to the outdoor air from the outdoor unit in cooling mode.

10. Total heating capacityreal \(\geq 0\)

The rate at which heat is added to the indoor unit air stream in heating mode.

11. Heat absorption ratereal \(\geq 0\)

The rate at which heat is absorbed from the outdoor air by the outdoor unit in heating mode.

12. Total power consumptionreal \(\geq 0\)

The total power input (compressor, indoor fan and outdoor fan) required to operate the heat pump.

13. Coefficient of performance (COP)real \(\geq 0\)

The ratio between the capacity (heating or cooling depending on the operating mode) and the total input power.

14. Energy efficiency rating (EER)real \(\geq 0\)

Same as the COP, but with the capacity expressed in BTU/h and the input power expressed in watts.

15. Indoor fan powerreal \(\geq 0\)

The rate at which the indoor unit fan is consuming energy.

16. Outdoor fan powerreal \(\geq 0\)

The rate at which the outdoor unit fan is consuming energy.

17. Compressor powerreal \(\geq 0\)

The rate at which the heat pump compressor is consuming energy.

18. Compressor frequencyreal \(\geq 0\)

The actual frequency of the heat pump compressor. It might be different from the one asked by the compressor if the heat pump shuts down (see output 22). It has the same units as the rated compressor frequency.

19. Condensate temperaturereal

The temperature of the condensate exiting the indoor unit in cooling mode.

20. Condensate mass flow ratereal \(\geq 0\)

The mass flow rate of the condensate exiting the indoor unit in cooling mode.

21. Defrost modeinteger \(\in \{0, 1, 2\}\)

The defrost mode of the heat pump.

\(0\)

Defrost mode

\(1\)

Recovery mode

\(2\)

Steady-state mode
22. Forced shutdown signalinteger \(\in \{0, 1\}\)

Returns \(0\) if the heat pump works noramlly, and \(1\) if it is shutdown because of an invalid set of input conditions.

Performance file

The Type 3254 relies on performance maps to evaluate the heat pump performance. Therefore, performance maps must be provided in the form of performance files—one for each operating mode. Those performance files must follow a specific format, detailed below. Adequately formatting the performance file can be cumbersome, and sometimes performance data is insufficient to cover all of the performance map quantities, as is genenrally the case with manufacturer data. Fortunately, there is a preprocessing tool available to remedy both of those problems.

Performance maps are represented as multidimensional arrays, each dimension corresponding to a certain input quantity and having a certain number of entries. The performance maps input quantities must include

  • the room dry-bulb temperature,

  • the outdoor dry-bulb temperature,

  • the normalized indoor volumetric air flow rate,

  • the normalized compressor frequency.

Cooling performance maps must also include the room wet-bulb temperature, to determine the sensible and latent capacity fractions. This means that heating performance maps have four dimensions, while cooling performance maps have five. Regarding the outputs, heating performance maps must provide values for the total input power and the total heating capacity. Cooling performance maps must also provide the total input power, along with the sensible and latent capacities.

Below are two examples of performance files, one for cooling and one for heating mode. Because there are many dimensions involved, performance files are ususally quite long, so only the first few lines are shown. The performance file begins by providing the dimensions of the performance map, along with the operating range associated with each input quantity. Then, it specifies the entries along each dimension, and finally the output values for every combination of the specified entries. Note that the input quantities must always be specified in the same order (room dry-bulb temperature first, then room wet-bulb temperature in cooling mode, then outdoor temperature, etc.). The firsts columns contain the entries combinations of each input quantity, with the rightmost quantity (the frequency) varying first. This ensures that the outut values are provided in the right order.

Example of cooling performance file.
 1!# This is a data file for Type 3254. Do not change the format.
 2!# In PARTICULAR, LINES STARTING WITH !# MUST BE LEFT IN THE FILE AT THEIR LOCATION.
 3!# Comments within "normal lines" (not starting with !#) are optional but the data must be there.
 4!#
 5!# Independent variables
 6!#
 7!# Number of Tdbr data points, lower bound, upper bound
 8   6 17.8 32.2
 9!# Number of Twbr data points, lower bound, upper bound
10   6 12.2 22.8
11!# Number of Tdbo data points, lower bound, upper bound
12   12 -10.0 46.0
13!# Number of AFR data points, lower bound, upper bound
14   2 1e-05 1.0
15!# Number of freq data points, lower bound, upper bound
16   14 0 1.4
17!# Tdbr values
18   17.8 21.1 23.9 26.7 29.4 32.2
19!# Twbr values
20   12.2 15.6 17.2 19.4 21.7 22.8
21!# Tdbo values
22   -10.0 -5.0 0.0 5.0 10.0 15.0 19.4 25.0 30.6 35.0 40.0 46.0
23!# AFR values
24   1e-05 1.0
25!# freq values
26   0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4
27!#
28!# Performance map
29!#
30!#   Tdbr    Twbr    Tdbo    AFR     freq    power         sensible_capacity latent_capacity
31     17.8    12.2    -10.0   1e-05   0.1     0.0032678034    0.0078270881    0.0095924383
32     17.8    12.2    -10.0   1e-05   0.2     0.015247431     0.0365067728    0.0447406448
33     17.8    12.2    -10.0   1e-05   0.3     0.0370154551    0.0862034025    0.1056460355
34     17.8    12.2    -10.0   1e-05   0.4     0.0683302257    0.148510872     0.1820065612
35     17.8    12.2    -10.0   1e-05   0.5     0.1080097759    0.211626558     0.2593575915
36     17.8    12.2    -10.0   1e-05   0.6     0.1541484803    0.2658985541    0.3258702935
37     17.8    12.2    -10.0   1e-05   0.7     0.2043652562    0.3075138351    0.3768716382
38     17.8    12.2    -10.0   1e-05   0.8     0.2560852354    0.3384178314    0.4147458357
39     17.8    12.2    -10.0   1e-05   0.9     0.3068232438    0.363399964     0.4453625305
40     17.8    12.2    -10.0   1e-05   1.0     0.3544303797    0.386779851     0.4740156035
41     17.8    12.2    -10.0   1e-05   1.1     0.3972710888    0.4105953643    0.5032025554
42     17.8    12.2    -10.0   1e-05   1.2     0.4343122105    0.4346359002    0.5326652823
43     17.8    12.2    -10.0   1e-05   1.3     0.4651227291    0.4575091829    0.5606974894
44     17.8    12.2    -10.0   1e-05   1.4     0.4897987153    0.4777544533    0.5855089526
45     17.8    12.2    -10.0   1.0     0.1     0.0032678034    0.0078270881    0.0095924383
46     17.8    12.2    -10.0   1.0     0.2     0.015247431     0.0365067728    0.0447406448
47     17.8    12.2    -10.0   1.0     0.3     0.0370154551    0.0862034025    0.1056460355
48     17.8    12.2    -10.0   1.0     0.4     0.0683302257    0.148510872     0.1820065612
49     17.8    12.2    -10.0   1.0     0.5     0.1080097759    0.211626558     0.2593575915
50     17.8    12.2    -10.0   1.0     0.6     0.1541484803    0.2658985541    0.3258702935
51     17.8    12.2    -10.0   1.0     0.7     0.2043652562    0.3075138351    0.3768716382
52     17.8    12.2    -10.0   1.0     0.8     0.2560852354    0.3384178314    0.4147458357
53     17.8    12.2    -10.0   1.0     0.9     0.3068232438    0.363399964     0.4453625305
54     17.8    12.2    -10.0   1.0     1.0     0.3544303797    0.386779851     0.4740156035
55     17.8    12.2    -10.0   1.0     1.1     0.3972710888    0.4105953643    0.5032025554
56     17.8    12.2    -10.0   1.0     1.2     0.4343122105    0.4346359002    0.5326652823
57     17.8    12.2    -10.0   1.0     1.3     0.4651227291    0.4575091829    0.5606974894
58     17.8    12.2    -10.0   1.0     1.4     0.4897987153    0.4777544533    0.5855089526
59     17.8    12.2    -5.0    1e-05   0.1     0.0038513398    0.0077754241    0.0095291219
60     17.8    12.2    -5.0    1e-05   0.2     0.0179701865    0.036265804     0.044445327

Example of heating performance file.
 1!# This is a data file for Type 3254. Do not change the format.
 2!# In PARTICULAR, LINES STARTING WITH !# MUST BE LEFT IN THE FILE AT THEIR LOCATION.
 3!# Comments within "normal lines" (not starting with !#) are optional but the data must be there.
 4!#
 5!# Independent variables
 6!#
 7!# Number of Tdbr data points, lower bound, upper bound
 8   4 15.6 23.9
 9!# Number of Tdbo data points, lower bound, upper bound
10   10 -26.1 15.0
11!# Number of AFR data points, lower bound, upper bound
12   2 1e-05 1.0
13!# Number of freq data points, lower bound, upper bound
14   20 0 2
15!# Tdbr values
16   15.6 18.3 21.1 23.9
17!# Tdbo values
18   -26.1 -20.6 -15.0 -10.0 -5.0 0.0 5.0 8.3 10.0 15.0
19!# AFR values
20   1e-05 1.0
21!# freq values
22   0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0
23!#
24!# Performance map
25!#
26!#   Tdbr    Tdbo    AFR     freq    power           capacity
27     15.6    -26.1   1e-05   0.1     0.003178591     0.0025479775
28     15.6    -26.1   1e-05   0.2     0.0186176684    0.0149240341
29     15.6    -26.1   1e-05   0.3     0.0520713887    0.0417407361
30     15.6    -26.1   1e-05   0.4     0.1072392615    0.0859636323
31     15.6    -26.1   1e-05   0.5     0.1861736662    0.1492379224
32     15.6    -26.1   1e-05   0.6     0.2892808725    0.2305285764
33     15.6    -26.1   1e-05   0.7     0.4153039359    0.3189541754
34     15.6    -26.1   1e-05   0.8     0.5613908536    0.4028984669
35     15.6    -26.1   1e-05   0.9     0.723289038     0.4733228775
36     15.6    -26.1   1e-05   1.0     0.8956723774    0.5262791482
37     15.6    -26.1   1e-05   1.1     1.0725789877    0.5634360902
38     15.6    -26.1   1e-05   1.2     1.2479148976    0.5901976742
39     15.6    -26.1   1e-05   1.3     1.4159640763    0.612731807
40     15.6    -26.1   1e-05   1.4     1.5718411744    0.6355189604
41     15.6    -26.1   1e-05   1.5     1.7118311746    0.6603478707
42     15.6    -26.1   1e-05   1.6     1.833578394     0.6867006008
43     15.6    -26.1   1e-05   1.7     1.9361121244    0.7128479986
44     15.6    -26.1   1e-05   1.8     2.0197222658    0.7369319946
45     15.6    -26.1   1e-05   1.9     2.0857201122    0.757631318
46     15.6    -26.1   1e-05   2.0     2.1361327416    0.7743642738
47     15.6    -26.1   1.0     0.1     0.003178591     0.0025479775
48     15.6    -26.1   1.0     0.2     0.0186176684    0.0149240341
49     15.6    -26.1   1.0     0.3     0.0520713887    0.0417407361
50     15.6    -26.1   1.0     0.4     0.1072392615    0.0859636323
51     15.6    -26.1   1.0     0.5     0.1861736662    0.1492379224
52     15.6    -26.1   1.0     0.6     0.2892808725    0.2305285764
53     15.6    -26.1   1.0     0.7     0.4153039359    0.3189541754
54     15.6    -26.1   1.0     0.8     0.5613908536    0.4028984669
55     15.6    -26.1   1.0     0.9     0.723289038     0.4733228775
56     15.6    -26.1   1.0     1.0     0.8956723774    0.5262791482
57     15.6    -26.1   1.0     1.1     1.0725789877    0.5634360902
58     15.6    -26.1   1.0     1.2     1.2479148976    0.5901976742
59     15.6    -26.1   1.0     1.3     1.4159640763    0.612731807
60     15.6    -26.1   1.0     1.4     1.5718411744    0.6355189604