Loading (50 kb)...'
(continued)
where,
?tdef = the time between defrost terminations (in hours) or 1.5, whichever is greater.
?tmax = maximum time between defrosts as allowed by the controls (in hours) or 12, whichever is less.
b. For two-capacity heat pumps and for section 3.6.2 units, evaluate the above equation using the ?tdef that applies based on the Frost Accumulation Test conducted at high capacity and/or at the Heating Certified Air Volume Rate. For variable-speed heat pumps, evaluate ?tdef based on the required Frost Accumulation Test conducted at the intermediate compressor speed.
3.10 Test procedures for steady-state Low Temperature heating mode tests (the H3, H32, and H31 Tests). Except for the modifications noted in this section, conduct the Low Temperature heating mode test using the same approach as specified in section 3.7 for the Maximum and High Temperature tests. After satisfying the section 3.7 requirements for the pretest interval but before beginning to collect data to determine Q hk(17) and E hk(17), conduct a defrost cycle. This defrost cycle may be manually or automatically initiated. The defrost sequence must be terminated by the action of the heat pump's defrost controls. Begin the 30-minute data collection interval described in section 3.7, from which Q hk(17) and E hk(17) are determined, no sooner than 10 minutes after defrost termination. Defrosts should be prevented over the 30-minute data collection interval.
3.11 Additional requirements for the secondary test methods. Prior to evaluating if the energy balance specified in section 3.1.1 is obtained, make an adjustment to account for the energy loss within the air duct that connects the indoor coil and the location where the outlet dry-bulb temperature is measured. If using the Outdoor Air Enthalpy Method, make an adjustment to account for the energy loss within the air duct that connects the outdoor coil and the location where the outlet temperature is measured. In all cases, apply the correction to the indoor space conditioning capacity that is determined using the secondary test method.
3.11.1 If using the Outdoor Air Enthalpy Method as the secondary test method. During the “official” test, the outdoor air-side test apparatus described in section 2.10.1 is connected to the outdoor unit. To help compensate for any effect that the addition of this test apparatus may have on the unit's performance, conduct a “preliminary” test where the outdoor air-side test apparatus is disconnected. Conduct a preliminary test prior to the first section 3.2 steady-state cooling mode test and prior to the first section 3.6 steady-state heating mode test. No other preliminary tests are required so long as the unit operates the outdoor fan during all cooling mode steady-state tests at the same speed and all heating mode steady-state tests at the same speed. If using more than one outdoor fan speed for the cooling mode steady-state tests, however, conduct a preliminary test prior to each cooling mode test where a different fan speed is first used. This same requirement applies for the heating mode tests.
3.11.1.1 If a preliminary test precedes the official test. a. The test conditions for the preliminary test are the same as specified for the official test. Connect the indoor air-side test apparatus to the indoor coil; disconnect the outdoor air-side test apparatus. Allow the test room reconditioning apparatus and the unit being tested to operate for at least one hour. After attaining equilibrium conditions, measure the following quantities at equal intervals that span 10 minutes or less:
1. The section 2.10.1 evaporator and condenser temperatures or pressures;
2. Parameters required according to the Indoor Air Enthalpy Method.
Continue these measurements until a 30-minute period (e.g., four consecutive 10-minute samples) is obtained where the Table 7 or Table 13, whichever applies, test tolerances are satisfied.
b. After collecting 30 minutes of steady-state data, reconnect the outdoor air-side test apparatus to the unit. Adjust the exhaust fan of the outdoor airflow measuring apparatus until averages for the evaporator and condenser temperatures, or the saturated temperatures corresponding to the measured pressures, agree within ±0.5 °F of the averages achieved when the outdoor air-side test apparatus was disconnected. Calculate the averages for the reconnected case using five or more consecutive readings taken at one minute intervals. Make these consecutive readings after re-establishing equilibrium conditions and before initiating the official test.
3.11.1.2 If a preliminary test does not precede the official test. Connect the outdoor-side test apparatus to the unit. Adjust the exhaust fan of the outdoor airflow measuring apparatus to achieve the same external static pressure as measured during the prior preliminary test conducted with the unit operating in the same cooling or heating mode at the same outdoor fan speed.
3.11.1.3 Official test. a. Continue (preliminary test was conducted) or begin (no preliminary test) the official test by making measurements for both the Indoor and Outdoor Air Enthalpy Methods at equal intervals that span 10 minutes or less. Discontinue these measurement only after obtaining a 30-minute period where the specified test condition and test operating tolerances are satisfied. To constitute a valid official test:
(1) Achieve the energy balance specified in section 3.1.1; and,
(2) For cases where a preliminary test is conducted, the capacities determined using the Indoor Air Enthalpy Method from the official and preliminary test periods must agree within 2.0 percent.
b. For space cooling tests, calculate capacity from the outdoor air enthalpy measurements as specified in section 7.3.3.2 of ASHRAE Standard 37–88 (incorporated by reference, see §430.22). Calculate heating capacity based on outdoor air enthalpy measurements as specified in section 7.3.4.2 of the same ASHRAE Standard. Adjust outdoor side capacities according to section 7.3.3.3 of ASHRAE Standard 37–88 (incorporated by reference, see §430.22) to account for line losses when testing split systems. Do not correct the average electrical power measurement as described in section 8.5.3 of ASHRAE Standard 37–88 (incorporated by reference, see §430.22).
3.11.2 If using the Compressor Calibration Method as the secondary test method.
a. Conduct separate calibration tests using a calorimeter to determine the refrigerant flow rate. Or for cases where the superheat of the refrigerant leaving the evaporator is less than 5 °F, use the calorimeter to measure total capacity rather than refrigerant flow rate. Conduct these calibration tests at the same test conditions as specified for the tests in this Appendix. Operate the unit for at least one hour or until obtaining equilibrium conditions before collecting data that will be used in determining the average refrigerant flow rate or total capacity. Sample the data at equal intervals that span 10 minutes or less. Determine average flow rate or average capacity from data sampled over a 30-minute period where the Table 7 (cooling) or the Table 13 (heating) tolerances are satisfied. Otherwise, conduct the calibration tests according to ASHRAE Standard 23–93 (incorporated by reference, see §430.22), ASHRAE Standard 41.9–00 (incorporated by reference, see §430.22), and section 7.5 of ASHRAE Standard 37–88 (incorporated by reference, see §430.22).
b. Calculate space cooling and space heating capacities using the compressor calibration method measurements as specified in sections 7.5.7 and 7.5.8, respectively, of ASHRAE Standard 37–88 (incorporated by reference, see §430.22).
3.11.3 If using the Refrigerant Enthalpy Method as the secondary test method. Conduct this secondary method according to section 7.6 of ASHRAE Standard 37–88 (incorporated by reference, see §430.22). Calculate space cooling and space heating capacities using the refrigerant enthalpy method measurements as specified in sections 7.6.4 and 7.6.5, respectively, of the same ASHRAE Standard.
3.12 Rounding of space conditioning capacities for reporting purposes.
a. When reporting rated capacities, round them off as follows:
1. For capacities less than 20,000 Btu/h, round to the nearest 100 Btu/h.
2. For capacities between 20,000 and 37,999 Btu/h, round to the nearest 200 Btu/h.
3. For capacities between 38,000 and 64,999 Btu/h, round to the nearest 500 Btu/h.
b. For the capacities used to perform the section 4 calculations, however, round only to the nearest integer.
4. CALCULATIONS OF SEASONAL PERFORMANCE DESCRIPTORS
4.1 Seasonal Energy Efficiency Ratio (SEER) Calculations. SEER must be calculated as follows: For equipment covered under sections 4.1.2, 4.1.3, and 4.1.4, evaluate the seasonal energy efficiency ratio,
where,
the ratio of the total space cooling provided during periods of the space cooling season when the outdoor temperature fell within the range represented by bin temperature Tj to the total number of hours in the cooling season (N), Btu/h.
the electrical energy consumed by the test unit during periods of the space cooling season when the outdoor temperature fell within the range represented by bin temperature Tj to the total number of hours in the cooling season (N), W.
Tj = the outdoor bin temperature, °F. Outdoor temperatures are grouped or “binned.” Use bins of 5 °F with the 8 cooling season bin temperatures being 67, 72, 77, 82, 87, 92, 97, and 102 °F.
j = the bin number. For cooling season calculations, j ranges from 1 to 8.
Additionally, for sections 4.1.2, 4.1.3, and 4.1.4, use a building cooling load, BL(Tj). When referenced, evaluate BL(Tj) for cooling using,
where,
Q ck=2(95) = the space cooling capacity determined from the A2 Test and calculated as specified in section 3.3, Btu/h.
1.1 = sizing factor, dimensionless.
The temperatures 95 °F and 65 °F in the building load equation represent the selected outdoor design temperature and the zero-load base temperature, respectively.
4.1.1 SEER calculations for an air conditioner or heat pump having a single-speed compressor that was tested with a fixed-speed indoor fan installed, a constant-air-volume-rate indoor fan installed, or with no indoor fan installed. a. Evaluate the seasonal energy efficiency ratio, expressed in units of Btu/watt-hour, using:
SEER = PLF(0.5) · EERB
where,
the energy efficiency ratio determined from the B Test described in sections 3.2.1, 3.1.4.1, and 3.3, Btu/h per watt.
PLF(0.5) = 1 - 0.5 · CDc, the part-load performance factor evaluated at a cooling load factor of 0.5, dimensionless.
b. Refer to section 3.3 regarding the definition and calculation of Q c(82) and E c(82). If the optional tests described in section 3.2.1 are not conducted, set the cooling mode cyclic degradation coefficient, CDc, to the default value specified in section 3.5.3. If these optional tests are conducted, set CDc to the lower of:
1. The value calculated as per section 3.5.3; or
2. The section 3.5.3 default value of 0.25.
4.1.2 SEER calculations for an air conditioner or heat pump having a single-speed compressor and a variable-speed variable-air-volume-rate indoor fan.
4.1.2.1 Units covered by section 3.2.2.1 where indoor fan capacity modulation correlates with the outdoor dry bulb temperature. The manufacturer must provide information on how the indoor air volume rate or the indoor fan speed varies over the outdoor temperature range of 67 °F to 102 °F. Calculate SEER using Equation 4.1–1. Evaluate the quantity qc(Tj)/N in Equation 4.1–1 using,
where,
whichever is less; the cooling mode load factor for temperature bin j, dimensionless.
Q c(Tj) = the space cooling capacity of the test unit when operating at outdoor temperature, Tj, Btu/h.
nj/N = fractional bin hours for the cooling season; the ratio of the number of hours during the cooling season when the outdoor temperature fell within the range represented by bin temperature Tj to the total number of hours in the cooling season, dimensionless.
a. For the space cooling season, assign nj/N as specified in Table 16. Use Equation 4.1–2 to calculate the building load, BL(Tj). Evaluate Q c(Tj) using,
where,
the space cooling capacity of the test unit at outdoor temperature Tj if operated at the Cooling Minimum Air Volume Rate, Btu/h.
the space cooling capacity of the test unit at outdoor temperature Tj if operated at the Cooling Certified Air Volume Rate, Btu/h.
b. For units where indoor fan speed is the primary control variable, FPck=1 denotes the fan speed used during the required A1 and B1 Tests (see section 3.2.2.1), FPck=2 denotes the fan speed used during the required A2 and B2 Tests, and FPc(Tj) denotes the fan speed used by the unit when the outdoor temperature equals Tj. For units where indoor air volume rate is the primary control variable, the three FPc's are similarly defined only now being expressed in terms of air volume rates rather than fan speeds. Refer to sections 3.2.2.1, 3.1.4 to 3.1.4.2, and 3.3 regarding the definitions and calculations of Q ck=1(82), Q ck=1(95),Q c k=2(82), and Q ck=2(95).
Calculate ec(Tj)/N in Equation 4.1–1 using,
where,
PLFj = 1 - CDc · [1 - X(Tj)], the part load factor, dimensionless.
E c(Tj) = the electrical power consumption of the test unit when operating at outdoor temperature Tj, W.
c. The quantities X(Tj) and nj /N are the same quantities as used in Equation 4.1.2–1. If the optional tests described in section 3.2.2.1 and Table 4 are not conducted, set the cooling mode cyclic degradation coefficient, CDc, to the default value specified in section 3.5.3. If these optional tests are conducted, set CDc to the lower of:
1. The value calculated as per section 3.5.3; or
2.The section 3.5.3 default value of 0.25.
d. Evaluate E c(Tj) using,
where
the electrical power consumption of the test unit at outdoor temperature Tj if operated at the Cooling Minimum Air Volume Rate, W.
the electrical power consumption of the test unit at outdoor temperature Tj if operated at the Cooling Certified Air Volume Rate, W.
e. The parameters FPck=1, and FPck=2, and FPc(Tj) are the same quantities that are used when evaluating Equation 4.1.2–2. Refer to sections 3.2.2.1, 3.1.4 to 3.1.4.2, and 3.3 regarding the definitions and calculations of E ck=1(82), E ck=1(95), E ck=2(82), and E ck=2(95).
4.1.2.2 Units covered by section 3.2.2.2 where indoor fan capacity modulation is used to adjust the sensible to total cooling capacity ratio. Calculate SEER as specified in section 4.1.1.
4.1.3 SEER calculations for an air conditioner or heat pump having a two-capacity compressor. Calculate SEER using Equation 4.1–1. Evaluate the space cooling capacity, Q ck=1(Tj), and electrical power consumption, E ck=1(Tj), of the test unit when operating at low compressor capacity and outdoor temperature Tj using,
where Q ck=1(95) and E ck=1(95) are determined from the A1 Test, Q ck=1(82) and E ck=1(82) are determined from the B1 Test, and all are calculated as specified in section 3.3. For two-capacity units that lock out low capacity operation at outdoor temperatures less than 95°F (but greater than 82°F), use Equations 4.1.4–1 and 4.1.4–2 rather than Equations 4.1.3–1 and 4.1.3–2 for estimating performance at low compressor capacity. Evaluate the space cooling capacity, Q ck=2(Tj), and electrical power consumption, E ck=2(Tj), of the test unit when operating at high compressor capacity and outdoor temperature Tj using,
where Q ck=2(95) and E ck=2(95) are determined from the A2 Test, Q ck=2(82), and E ck=2(82), are determined from the B2 Test, and all are calculated as specified in section 3.3.
The calculation of Equation 4.1–1 quantities qc(Tj)/N and ec(Tj)/N differs depending on whether the test unit would operate at low capacity (section 4.1.3.1), cycle between low and high capacity (section 4.1.3.2), or operate at high capacity (sections 4.1.3.3 and 4.1.3.4) in responding to the building load. For units that lock out low capacity operation at higher outdoor temperatures, the manufacturer must supply information regarding this temperature so that the appropriate equations are used. Use Equation 4.1–2 to calculate the building load, BL(Tj), for each temperature bin.
4.1.3.1 Steady-state space cooling capacity at low compressor capacity is greater than or equal to the building cooling load at temperature Tj, Q ck=1(Tj) = BL(Tj).
where,
Xk=1(Tj) = BL(Tj)/Q ck=1(Tj), the cooling mode low capacity load factor for temperature bin j, dimensionless.
PLFj = 1 - CDc · [1 - Xk=1(Tj)], the part load factor, dimensionless.
fractional bin hours for the cooling season; the ratio of the number of hours during the cooling season when the outdoor temperature fell within the range represented by bin temperature Tj to the total number of hours in the cooling season, dimensionless.
Obtain the fractional bin hours for the cooling season, nj/N, from Table 16. Use Equations 4.1.3–1 and 4.1.3–2, respectively, to evaluate Q ck=1(Tj) and E ck=1(Tj). If the optional tests described in section 3.2.3 and Table 5 are not conducted, set the cooling mode cyclic degradation coefficient, CDc, to the default value specified in section 3.5.3. If these optional tests are conducted, set CDc to the lower of:
a. The value calculated according to section 3.5.3; or
b. The section 3.5.3 default value of 0.25.
Table 16_Distribution of Fractional Hours Within Cooling Season Temperature Bins
----------------------------------------------------------------------------------------------------------------
Representative
Bin number, j Bin temperature temperature for Fraction of of total
range °F bin °F temperature bin hours, nj/N
----------------------------------------------------------------------------------------------------------------
1........................................... 65-69 67 0.214
2........................................... 70-74 72 0.231
3........................................... 75-79 77 0.216
4........................................... 80-84 82 0.161
5........................................... 85-89 87 0.104
6........................................... 90-94 92 0.052
7........................................... 95-99 97 0.018
8........................................... 100-104 102 0.004
----------------------------------------------------------------------------------------------------------------
4.1.3.2 Unit alternates between high (k=2) and low (k=1) compressor capacity to satisfy the building cooling load at temperature Tj, Q ck=1(Tj) < BL(Tj) < Q ck=2(Tj).
where,
the cooling mode, low capacity load factor for temperature bin j, dimensionless.
Xk=2(Tj) = 1 - Xk=1(Tj), the cooling mode, high capacity load factor for temperature bin j, dimensionless.
Obtain the fractional bin hours for the cooling season, nj/N, from Table 16. Use Equations 4.1.3–1 and 4.1.3–2, respectively, to evaluate Q ck=1(Tj) and E ck=1(Tj). Use Equations 4.1.3–3 and 4.1.3–4, respectively, to evaluate Q ck=2(Tj) and E ck=2(Tj).
4.1.3.3 Unit only operates at high (k=2) compressor capacity at temperature Tj and its capacity is greater than the building cooling load, BL(Tj) < Q ck=2(Tj). This section applies to units that lock out low compressor capacity operation at higher outdoor temperatures.
where,
Xk=2(Tj) = BL(Tj)/Q ck=2(Tj), the cooling mode high capacity load factor for temperature bin j, dimensionless.
PLFj = 1 - CDc · [1 - Xk=2(Tj)], the part load factor, dimensionless.
Obtain the fractional bin hours for the cooling season, nj/N, from Table 16. Use Equations 4.1.3–3 and 4.1.3–4, respectively, to evaluate Q ck=2(Tj) and E ck=2(Tj). When evaluating the above equation for part load factor at high capacity, use the same value of CDc as used in the section 4.1.3.1 calculations.
4.1.3.4 Unit must operate continuously at high (k=2) compressor capacity at temperature Tj, BL(Tj) = Q ck=2(Tj).
Obtain the fractional bin hours for the cooling season, nj/N, from Table 16. Use Equations 4.1.3–3 and 4.1.3–4, respectively, to evaluate Q ck=2(Tj) and E ck=2(Tj).
4.1.4 SEER calculations for an air conditioner or heat pump having a variable-speed compressor. Calculate SEER using Equation 4.1–1. Evaluate the space cooling capacity, Q ck=1(Tj), and electrical power consumption, E ck=1(Tj), of the test unit when operating at minimum compressor speed and outdoor temperature Tj. Use,
where Q ck=1(82) and E ck=1(82) are determined from the B1 Test, Q ck=1(67) and E ck=1(67) are determined from the F1 Test, and all four quantities are calculated as specified in section 3.3. Evaluate the space cooling capacity, Q ck=2(Tj), and electrical power consumption, E ck=2(Tj), of the test unit when operating at maximum compressor speed and outdoor temperature Tj. Use Equations 4.1.3–3 and 4.1.3–4, respectively, where Q ck=2(95) and E ck=2(95) are determined from the A2 Test, Q ck=2(82) and E ck=2(82) are determined from the B2 Test, and all four quantities are calculated as specified in section 3.3. Calculate the space cooling capacity, Q ck=v(Tj), and electrical power consumption, E ck=v(Tj), of the test unit when operating at outdoor temperature Tj and the intermediate compressor speed used during the section 3.2.4 (and Table 6) EV Test using,
where Q ck=v(87) and E ck=v(87) are determined from the EV Test and calculated as specified in section 3.3. Approximate the slopes of the k = v intermediate speed cooling capacity and electrical power input curves, MQ and ME, as follows:
where,
Calculating Equation 4.1–1 quantities
differs depending upon whether the test unit would operate at minimum speed (section 4.1.4.1), operate at an intermediate speed (section 4.1.4.2), or operate at maximum speed (section 4.1.4.3) in responding to the building load. Use Equation 4.1–2 to calculate the building load, BL(Tj), for each temperature bin.
4.1.4.1 Steady-state space cooling capacity when operating at minimum compressor speed is greater than or equal to the building cooling load at temperature Tj, Q ck=1(Tj) = BL(Tj).
where,
Xk=1(Tj) = BL(Tj) / Q ck=1(Tj), the cooling mode minimum speed load factor for temperature bin j, dimensionless.
PLFj = 1 - CDc · [1 - Xk=1(Tj)], the part load factor, dimensionless.
nj/N = fractional bin hours for the cooling season; the ratio of the number of hours during the cooling season when the outdoor temperature fell within the range represented by bin temperature Tj to the total number of hours in the cooling season, dimensionless.
Obtain the fractional bin hours for the cooling season, nj/N, from Table 16. Use Equations 4.1.4–1 and 4.1.4–2, respectively, to evaluate Q ck=1(Tj) and E ck=1(Tj). If the optional tests described in section 3.2.4 and Table 6 are not conducted, set the cooling mode cyclic degradation coefficient, CDc, to the default value specified in section 3.5.3. If these optional tests are conducted, set CDc to the lower of:
a. The value calculated according to section 3.5.3; or
b. The section 3.5.3 default value of 0.25.
4.1.4.2 Unit operates at an intermediate compressor speed (k=i) in order to match the building cooling load at temperature Tj,Q ck=1(Tj) < BL(Tj) < Q ck=2(Tj).
where,
Q ck=i(Tj) = BL(Tj), the space cooling capacity delivered by the unit in matching the building load at temperature Tj, Btu/h. The matching occurs with the unit operating at compressor speed k = i.
the electrical power input required by the test unit when operating at a compressor speed of k = i and temperature Tj, W.
EERk=i(Tj) = the steady-state energy efficiency ratio of the test unit when operating at a compressor speed of k = i and temperature Tj, Btu/h per W.
Obtain the fractional bin hours for the cooling season, nj/N, from Table 16. For each temperature bin where the unit operates at an intermediate compressor speed, determine the energy efficiency ratio EERk=i(Tj) using,
EERk=i(Tj) = A + B · Tj + C · Tj 2 .
For each unit, determine the coefficients A, B, and C by conducting the following calculations once:
where,
Tl = the outdoor temperature at which the unit, when operating at minimum compressor speed, provides a space cooling capacity that is equal to the building load (Q ck=1(T1) = BL(T1)), °F. Determine T1 by equating Equations 4.1.4–1 and 4.1–2 and solving for outdoor temperature.
Tv = the outdoor temperature at which the unit, when operating at the intermediate compressor speed used during the section 3.2.4 EV Test, provides a space cooling capacity that is equal to the building load (Q ck=v (Tv) = BL(Tv)), °F. Determine Tv by equating Equations 4.1.4–3 and 4.1–2 and solving for outdoor temperature.
T2 = the outdoor temperature at which the unit, when operating at maximum compressor speed, provides a space cooling capacity that is equal to the building load (Q ck=2 (T2) = BL(T2)), °F. Determine T2 by equating Equations 4.1.3–3 and 4.1–2 and solving for outdoor temperature.
4.1.4.3 Unit must operate continuously at maximum (k=2) compressor speed at temperature Tj, BL(Tj) = Q ck=2(Tj). Evaluate the Equation 4.1–1 quantities
as specified in section 4.1.3.4 with the understanding that Q ck=2(Tj) and E ck=2(Tj) correspond to maximum compressor speed operation and are derived from the results of the tests specified in section 3.2.4.
4.2 Heating Seasonal Performance Factor (HSPF) Calculations. Unless an approved alternative rating method is used, as set forth in 10 CFR 430.24(m), Subpart B, HSPF must be calculated as follows: Six generalized climatic regions are depicted in Figure 2 and otherwise defined in Table 17. For each of these regions and for each applicable standardized design heating requirement, evaluate the heating seasonal performance factor using,
where,
eh(Tj)/N=
The ratio of the electrical energy consumed by the heat pump during periods of the space heating season when the outdoor temperature fell within the range represented by bin temperature Tj to the total number of hours in the heating season (N), W. For heat pumps having a heat comfort controller, this ratio may also include electrical energy used by resistive elements to maintain a minimum air delivery temperature (see 4.2.5).
RH(Tj)/N=
The ratio of the electrical energy used for resistive space heating during periods when the outdoor temperature fell within the range represented by bin temperature Tj to the total number of hours in the heating season (N),W. Except as noted in section 4.2.5, resistive space heating is modeled as being used to meet that portion of the building load that the heat pump does not meet because of insufficient capacity or because the heat pump automatically turns off at the lowest outdoor temperatures. For heat pumps having a heat comfort controller, all or part of the electrical energy used by resistive heaters at a particular bin temperature may be reflected in eh(Tj)/N (see 4.2.5).
Tj = the outdoor bin temperature, °F. Outdoor temperatures are “binned” such that calculations are only performed based one temperature within the bin. Bins of 5 °F are used.
nj/N=
Fractional bin hours for the heating season; the ratio of the number of hours during the heating season when the outdoor temperature fell within the range represented by bin temperature Tj to the total number of hours in the heating season, dimensionless. Obtain nj/N values from Table 17.
j = the bin number, dimensionless.
J = for each generalized climatic region, the total number of temperature bins, dimensionless. Referring to Table 17, J is the highest bin number (j) having a nonzero entry for the fractional bin hours for the generalized climatic region of interest.
Fdef = the demand defrost credit described in section 3.9.2, dimensionless.
BL(Tj) = the building space conditioning load corresponding to an outdoor temperature of Tj; the heating season building load also depends on the generalized climatic region's outdoor design temperature and the design heating requirement, Btu/h.
Table 17_Generalized Climatic Region Information
----------------------------------------------------------------------------------------------------------------
----------------------------------------------------------------------------------------------------------------
Region Number................................. I II III IV V VI
Heating Load Hours, HLH....................... 750 1250 1750 2250 2750 *2750
Outdoor Design Temperature, TOD............... 37 27 17 5 -10 30
-----------------------------------------------------------------
j Tj ( °F)............................... Fraction
al Bin
Hours, nj/
N
-----------------------------------------------------------------
1 62......................................... .291 .215 .153 .132 .106 .113
2 57......................................... .239 .189 .142 .111 .092 .206
3 52......................................... .194 .163 .138 .103 .086 .215
4 47......................................... .129 .143 .137 .093 .076 .204
5 42......................................... .081 .112 .135 .100 .078 .141
6 37......................................... .041 .088 .118 .109 .087 .076
7 32......................................... .019 .056 .092 .126 .102 .034
8 27......................................... .005 .024 .047 .087 .094 .008
9 22......................................... .001 .008 .021 .055 .074 .003
10 17......................................... 0 .002 .009 .036 .055 0
11 12......................................... 0 0 .005 .026 .047 0
12 7.......................................... 0 0 .002 .013 .038 0
13 2.......................................... 0 0 .001 .006 .029 0
14 -3......................................... 0 0 0 .002 .018 0
15 -8......................................... 0 0 0 .001 .010 0
16 -13........................................ 0 0 0 0 .005 0
17 -18........................................ 0 0 0 0 .002 0
18 -23........................................ 0 0 0 0 .001 0
----------------------------------------------------------------------------------------------------------------
* Pacific Coast Region.
Evaluate the building heating load using
where,
TOD = the outdoor design temperature, °F. An outdoor design temperature is specified for each generalized climatic region in Table 17.
C = 0.77, a correction factor which tends to improve the agreement between calculated and measured building loads, dimensionless.
DHR = the design heating requirement (see Definition 1.22), Btu/h.
Calculate the minimum and maximum design heating requirements for each generalized climatic region as follows:
and
where Q hk(47) is expressed in units of Btu/h and otherwise defined as follows:
1. For a single-speed heat pump tested as per section 3.6.1, Q hk(47) = Q h(47), the space heating capacity determined from the H1 Test.
2. For a variable-speed heat pump, a section 3.6.2 single-speed heat pump, or a two-capacity heat pump not covered by item 3, Q nk(47) = Q nk=2(47), the space heating capacity determined from the H12 Test.
3. For two-capacity, northern heat pumps (see Definition 1.46), Q kh(47) = Q k=1h(47), the space heating capacity determined from the H11 Test.
If the optional H1N Test is conducted on a variable-speed heat pump, the manufacturer has the option of defining Q kh(47) as specified above in item 2 or as Q kh(47)=Q k=Nh(47), the space heating capacity determined from the H1N Test.
For all heat pumps, HSPF accounts for the heating delivered and the energy consumed by auxiliary resistive elements when operating below the balance point. This condition occurs when the building load exceeds the space heating capacity of the heat pump condenser. For HSPF calculations for all heat pumps, see either section 4.2.1, 4.2.2, 4.2.3, or 4.2.4, whichever applies.
For heat pumps with heat comfort controllers (see Definition 1.28), HSPF also accounts for resistive heating contributed when operating above the heat-pump-plus-comfort-controller balance point as a result of maintaining a minimum supply temperature. For heat pumps having a heat comfort controller, see section 4.2.5 for the additional steps required for calculating the HSPF.
Table 18_Standardized Design Heating Requirements (Btu/h)
------------------------------------------------------------------------
------------------------------------------------------------------------
5,000.................................. 25,000 50,000 90,000
10,000................................. 30,000 60,000 100,000
15,000................................. 35,000 70,000 110,000
20,000................................. 40,000 80,000 130,000
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4.2.1 Additional steps for calculating the HSPF of a heat pump having a single-speed compressor that was tested with a fixed-speed indoor fan installed, a constant-air-volume-rate indoor fan installed, or with no indoor fan installed.
where,
whichever is less; the heating mode load factor for temperature bin j, dimensionless.
Q h(Tj) = the space heating capacity of the heat pump when operating at outdoor temperature Tj, Btu/h.
E h(Tj) = the electrical power consumption of the heat pump when operating at outdoor temperature Tj, W.
d(Tj) = the heat pump low temperature cut-out factor, dimensionless.
PLFj = 1 - C Dh · [1 -X(Tj)] the part load factor, dimensionless.
Use Equation 4.2–2 to determine BL(Tj). Obtain fractional bin hours for the heating season, nj/N, from Table 17. If the optional H1C Test described in section 3.6.1 is not conducted, set the heating mode cyclic degradation coefficient, CDh, to the default value specified in section 3.8.1. If this optional test is conducted, set C Dh to the lower of:
a. The value calculated according to section 3.8.1 or
b. The section 3.8.1 default value of 0.25.
Determine the low temperature cut-out factor using
where,
Toff = the outdoor temperature when the compressor is automatically shut off, °F. (If no such temperature exists, Tj is always greater than Toff and Ton).
Ton = the outdoor temperature when the compressor is automatically turned back on, if applicable, following an automatic shut-off, °F.
Calculate Q h(Tj) and E h(Tj) using,
where Q h(47) and E h(47) are determined from the H1 Test and calculated as specified in section 3.7; Q h(35) and E h(35) are determined from the H2 Test and calculated as specified in section 3.9.1; and Q h(17) and E h(17) are determined from the H3 Test and calculated as specified in section 3.10.
4.2.2 Additional steps for calculating the HSPF of a heat pump having a single-speed compressor and a variable-speed, variable-air-volume-rate indoor fan. The manufacturer must provide information about how the indoor air volume rate or the indoor fan speed varies over the outdoor temperature range of 65 °F to -23 °F. Calculate the quantities
in Equation 4.2–1 as specified in section 4.2.1 with the exception of replacing references to the H1C Test and section 3.6.1 with the H1C1 Test and section 3.6.2. In addition, evaluate the space heating capacity and electrical power consumption of the heat pump Q h(Tj) and E h(Tj) using
where the space heating capacity and electrical power consumption at both low capacity (k=1) and high capacity (k=2) at outdoor temperature Tj are determined using
For units where indoor fan speed is the primary control variable, FPhk=1 denotes the fan speed used during the required H11 and H31 Tests (see Table 10), FPhk=2 denotes the fan speed used during the required H12, H22, and H32 Tests, and FPh(Tj) denotes the fan speed used by the unit when the outdoor temperature equals Tj. For units where indoor air volume rate is the primary control variable, the three FPh's are similarly defined only now being expressed in terms of air volume rates rather than fan speeds. Determine Q hk=1(47) and E hk=1(47) from the H11 Test, and Q hk=2(47) and E hk=2(47) from the H12 Test. Calculate all four quantities as specified in section 3.7. Determine Q hk=1(35) and E hk=1(35) as specified in section 3.6.2; determine Q hk=2(35) and E hk=2(35) and from the H22 Test and the calculation specified in section 3.9. Determine Q hk=1(17) and E hk=1(17 from the H31 Test, and Q hk=2(17) and E hk=2(17) from the H32 Test. Calculate all four quantities as specified in section 3.10.
4.2.3 Additional steps for calculating the HSPF of a heat pump having a two-capacity compressor. The calculation of the Equation 4.2–1 quantities
differs depending upon whether the heat pump would operate at low capacity (section 4.2.3.1), cycle between low and high capacity (Section 4.2.3.2), or operate at high capacity (sections 4.2.3.3 and 4.2.3.4) in responding to the building load. For heat pumps that lock out low capacity operation at low outdoor temperatures, the manufacturer must supply information regarding the cutoff temperature(s) so that the appropriate equations can be selected.
a. Evaluate the space heating capacity and electrical power consumption of the heat pump when operating at low compressor capacity and outdoor temperature Tj using
b. Evaluate the space heating capacity and electrical power consumption (Q hk=2(Tj) and E hk=2 (Tj)) of the heat pump when operating at high compressor capacity and outdoor temperature Tj by solving Equations 4.2.2–3 and 4.2.2–4, respectively, for k=2. Determine Q hk=1(62) and E hk=1(62) from the H01 Test, Q hk=1(47) and E hk=1(47) from the H11 Test, and Q hk=2(47) and E hk=2(47) from the H12 Test. Calculate all six quantities as specified in section 3.7. Determine Q hk=2(35) and E hk=2(35) from the H22 Test and, if required as described in section 3.6.3, determine Q hk=1(35) and E hk=1(35) from the H21 Test. Calculate the required 35 °F quantities as specified in section 3.9. Determine Q hk=2(17) and E hk=2(17) from the H32 Test and, if required as described in section 3.6.3, determine Q hk=1(17) and E hk=1(17) from the H31 Test. Calculate the required 17 °F quantities as specified in section 3.10.
4.2.3.1 Steady-state space heating capacity when operating at low compressor capacity is greater than or equal to the building heating load at temperature Tj, Q hk=1(Tj) = BL(Tj).
where,
Xk=1(Tj) = BL(Tj) / Q hk=1(Tj), the heating mode low capacity load factor for temperature bin j, dimensionless.
PLFj = 1 - CDh · [ 1 - Xk=1(Tj) ], the part load factor, dimensionless.
d'(Tj) = the low temperature cutoff factor, dimensionless.
If the optional H0C1 Test described in section 3.6.3 is not conducted, set the heating mode cyclic degradation coefficient, CDh, to the default value specified in section 3.8.1. If this optional test is conducted, set CDh to the lower of:
a. The value calculated according to section 3.8.1; or
b. The section 3.8.1 default value of 0.25.
Determine the low temperature cut-out factor using
where Toff and Ton are defined in section 4.2.1. Use the calculations given in section 4.2.3.3, and not the above, if:
(a) The heat pump locks out low capacity operation at low outdoor temperatures and
(b) Tj is below this lockout threshold temperature.
4.2.3.2 Heat pump alternates between high (k=2) and low (k=1) compressor capacity to satisfy the building heating load at a temperature Tj, Q hk=1(Tj) < BL(Tj) < Q hk=2(Tj).
Calculate
using Equation 4.2.3–2. Evaluate
using
where,
Xk=2(Tj) = 1 - Xk=1(Tj) the heating mode, high capacity load factor for temperature bin j, dimensionless.
Determine the low temperature cut-out factor, d'(Tj), using Equation 4.2.3–3.
4.2.3.3 Heat pump only operates at high (k=2) compressor capacity at temperature Tj and its capacity is greater than the building heating load, BL(Tj) < Q hk=2(Tj). This section applies to units that lock out low compressor capacity operation at low outdoor temperatures. Calculate
using Equation 4.2.3–2. Evaluate
using
where,
Xk=2(Tj)= BL(Tj)/Q hk=2(Tj).
PLFj = 1 - CDh [ 1 - Xk=2(Tj) ].
When evaluating the above equation for part load factor at high capacity, use the same value of CDh as used in the section 4.2.3.1 calculations. Determine the low temperature cut-out factor, d'(Tj), using Equation 4.2.3–3.
4.2.3.4 Heat pump must operate continuously at high (k=2) compressor capacity at temperature Tj, BL(Tj) = Q hk=2(Tj).
Where
4.2.4 Additional steps for calculating the HSPF of a heat pump having a variable-speed compressor. Calculate HSPF using Equation 4.2–1. Evaluate the space heating capacity, Q hk=1(Tj), and electrical power consumption, E hk=1(Tj), of the heat pump when operating at minimum compressor speed and outdoor temperature Tj using
where Q hk=1(62) and E hk=1(62) are determined from the H01 Test, Q hk=1(47) and E hk=1(47) are determined from the H11 Test, and all four quantities are calculated as specified in section 3.7. Evaluate the space heating capacity, Q hk=2(Tj), and electrical power consumption, E hk=2(Tj), of the heat pump when operating at maximum compressor speed and outdoor temperature Tj by solving Equations 4.2.2–3 and 4.2.2–4, respectively, for k=2. Determine the Equation 4.2.2–3 and 4.2.2–4 quantities Q hk=2(47) and E hk=2(47) from the H12 Test and the calculations specified in section 3.7. Determine Q hk=2(35) and E hk=2(35) from the H22 Test and the calculations specified in section 3.9 or, if the H22 Test is not conducted, by conducting the calculations specified in section 3.6.4. Determine Q hk=2(17) and E hk=2(17) from the H32 Test and the calculations specified in section 3.10. Calculate the space heating capacity, Q hk=v(Tj), and electrical power consumption, E hk=v(Tj), of the heat pump when operating at outdoor temperature Tj and the intermediate compressor speed used during the section 3.6.4 H2V Test using
where Q hk=v(35) and E hk=v(35) are determined from the H2V Test and calculated as specified in section 3.9. Approximate the slopes of the k=v intermediate speed heating capacity and electrical power input curves, MQ and ME, as follows:
where,
Use Equations 4.2.4–1 and 4.2.4–2, respectively, to calculate Q hk=1(35) and E hk=1(35).
The calculation of Equation 4.2–1 quantities
differs depending upon whether the heat pump would operate at minimum speed (section 4.2.4.1), operate at an intermediate speed (section 4.2.4.2), or operate at maximum speed (section 4.2.4.3) in responding to the building load.
4.2.4.1 Steady-state space heating capacity when operating at minimum compressor speed is greater than or equal to the building heating load at temperature Tj, Q hk=1(Tj = BL(Tj). Evaluate the Equation 4.2–1 quantities
as specified in section 4.2.3.1. Except now use Equations 4.2.4–1 and 4.2.4–2 to evaluate Q hk=1(Tj) and E hk=1(Tj), respectively, and replace section 4.2.3.1 references to “low capacity” and section 3.6.3 with “minimum speed” and section 3.6.4. Also, the last sentence of section 4.2.3.1 does not apply.
4.2.4.2 Heat pump operates at an intermediate compressor speed (k=i) in order to match the building heating load at a temperature Tj, Q hk=1(Tj) < BL(Tj) < Q hk=2(Tj). Calculate
using Equation 4.2.3–2 while evaluating
using,
where,
and d(Tj) is evaluated using Equation 4.2.3–3 while,
Q hk=i(Tj) = BL(Tj), the space heating capacity delivered by the unit in matching the building load at temperature (Tj), Btu/h. The matching occurs with the heat pump operating at compressor speed k=i.
COPk=i(Tj) = the steady-state coefficient of performance of the heat pump when operating at compressor speed k=i and temperature Tj, dimensionless.
For each temperature bin where the heat pump operates at an intermediate compressor speed, determine COPk=i(Tj) using,
COPk=i(Tj) = A + B . Tj + C . Tj 2 .
For each heat pump, determine the coefficients A, B, and C by conducting the following calculations once:
where,
T3 = the outdoor temperature at which the heat pump, when operating at minimum compressor speed, provides a space heating capacity that is equal to the building load (Q hk=1(T3) = BL(T3)), °F. Determine T3 by equating Equations 4.2.4–1 and 4.2–2 and solving for:
outdoor temperature.
Tvh = the outdoor temperature at which the heat pump, when operating at the intermediate compressor speed used during the section 3.6.4 H2V Test, provides a space heating capacity that is equal to the building load (Q hk=v(Tvh) = BL(Tvh)), °F. Determine Tvh by equating Equations 4.2.4–3 and 4.2–2 and solving for outdoor temperature.
T4 = the outdoor temperature at which the heat pump, when operating at maximum compressor speed, provides a space heating capacity that is equal to the building load (Q hk=2(T4) = BL(T4)), °F. Determine T4 by equating Equations 4.2.2–3 (k=2) and 4.2–2 and solving for outdoor temperature.
4.2.4.3 Heat pump must operate continuously at maximum (k=2) compressor speed at temperature Tj, BL(Tj) = Q hk=2(Tj). Evaluate the Equation 4.2–1 quantities
as specified in section 4.2.3.4 with the understanding that Q hk=2(Tj) and E hk=2(Tj) correspond to maximum compressor speed operation and are derived from the results of the specified section 3.6.4 tests.
4.2.5 Heat pumps having a heat comfort controller. Heat pumps having heat comfort controllers, when set to maintain a typical minimum air delivery temperature, will cause the heat pump condenser to operate less because of a greater contribution from the resistive elements. With a conventional heat pump, resistive heating is only initiated if the heat pump condenser cannot meet the building load (i.e., is delayed until a second stage call from the indoor thermostat). With a heat comfort controller, resistive heating can occur even though the heat pump condenser has adequate capacity to meet the building load (i.e., both on during a first stage call from the indoor thermostat). As a result, the outdoor temperature where the heat pump compressor no longer cycles (i.e., starts to run continuously), will be lower than if the heat pump did not have the heat comfort controller.
4.2.5.1 Heat pump having a heat comfort controller: additional steps for calculating the HSPF of a heat pump having a single-speed compressor that was tested with a fixed-speed indoor fan installed, a constant-air-volume-rate indoor fan installed, or with no indoor fan installed. Calculate the space heating capacity and electrical power of the heat pump without the heat comfort controller being active as specified in section 4.2.1 (Equations 4.2.1–4 and 4.2.1–5) for each outdoor bin temperature, Tj, that is listed in Table 17. Denote these capacities and electrical powers by using the subscript “hp” instead of “h.” Calculate the mass flow rate (expressed in pounds-mass of dry air per hour) and the specific heat of the indoor air (expressed in Btu/lbmda · °F) from the results of the H1 Test using:
where V s, V mx, v'n (or vn), and Wn are defined following Equation 3–1. For each outdoor bin temperature listed in Table 17, calculate the nominal temperature of the air leaving the heat pump condenser coil using,
Evaluate eh(Tj/N), RH(Tj)/N, X(Tj), PLFj, and d(Tj) as specified in section 4.2.1. For each bin calculation, use the space heating capacity and electrical power from Case 1 or Case 2, whichever applies.
Case 1. For outdoor bin temperatures where To(Tj) is equal to or greater than TCC (the maximum supply temperature determined according to section 3.1.9), determine Q h(Tj) and E h(Tj) as specified in section 4.2.1 (i.e., Q h(Tj) = Q hp(Tj) and E hp(Tj) = E hp(Tj)). Note: Even though To(Tj) = Tcc, resistive heating may be required; evaluate Equation 4.2.1–2 for all bins.
Case 2. For outdoor bin temperatures where To(Tj) > Tcc, determine Q h(Tj) and E h(Tj) using,
where,
Note: Even though To(Tj) < Tcc, additional resistive heating may be required; evaluate Equation 4.2.1–2 for all bins.
4.2.5.2 Heat pump having a heat comfort controller: additional steps for calculating the HSPF of a heat pump having a single-speed compressor and a variable-speed, variable-air-volume-rate indoor fan. Calculate the space heating capacity and electrical power of the heat pump without the heat comfort controller being active as specified in section 4.2.2 (Equations 4.2.2–1 and 4.2.2–2) for each outdoor bin temperature, Tj, that is listed in Table 17. Denote these capacities and electrical powers by using the subscript “hp” instead of “h.” Calculate the mass flow rate (expressed in pounds-mass of dry air per hour) and the specific heat of the indoor air (expressed in Btu/lbmda · °F) from the results of the H12 Test using: (continued)