Bryant HEAT RECOVERY VENTILATOR ERVBBLHA Product Data page 6

Ventilator Sizing
Tables 1 and 2 should be used to determine the required airflow for a home. These guidelines are taken from ASHRAE 62.2- -2007.
Table 1 – Ventilation Air Requirements, cfm
FLOOR
2
AREA (ft )
0---1 2---3
<1500 30 45
1501--- 3000 45 60
3001--- 4500 60 75
4501--- 6000 75 90
6001--- 7500 90 105
>7500 105 120
Although the ventilators process the outside air before it enters the home, additional heating and cooling loads need to be considered.
HEATING LOAD BTUH
Heating Load (Btuh) @
Outside
Inside Design Temp 72°F
Temp °F
ERV1150 ERV1200
–25 5186 8143
–20 4919 7723
–15 5075 7967
–10 4783 7509
–5 4491 7051
0 4200 6594
5 4234 6647
10 3918 6151
15 3958 6214
20 3611 5669
25 3264 5124
30 2916 4579
35 2569 4034
40 2222 3489
The heating load chart shows the heating loads in Btuh for a range
of winter design temperatures for each model of ventilator.
EXAMPLE: The heating design temperature for Little Rock, AR is
20_F. The additional heating load of the ERVBBLHA1200 at
20_F is 559 Btuh. This additional load should be taken into
consideration when sizing the heating equipment.
METHOD TO SIZE ERVs and HRVs
BEDROOMS
4---5 6---7 >7
60 75 90
75 90 105
90 105 120
105 120 135
120 135 150
135 150 165
HEATING AND COOLING LOAD CHARTS
HRV1150 HRV1250
6636 10603
6294 10057
5952 9510
5610 8964
5268 8417
4925 7871
4583 7324
4241 6777
3899 6231
3557 5684
3215 5138
2873 4591
2531 4045
2189 3498
Table 2 – Ventilation Air Requirements, L/s
FLOOR
2
AREA (m )
0---1 2---3
<139 14 21
139.1--- 279 21 28
279.1--- 418 28 35
418.1--- 557 35 42
557.1--- 697 42 50
>697 50 57
COOLING LOAD BTUH
Cooling Load (Btuh) @ Inside Design Temp
Outside
72°F and 50% Relative Humidity
Enthalpy
Btu/lb
ERV1150 ERV1200
30 380
31 618 1040
32 855 1441
33 1093 1841
34 1331 2241
35 1568 2641
36 1806 3041
37 2043 3441
38 2281 3842
39 2519 4242
40 2756 4642
41 2994 5042
42 3231 5442
The cooling load chart shows loads in Btuh as well. To use the
cooling load chart, first find the design enthalpy from a
psychrometric chart using the design dry bulb and wet bulb
temperatures. The cooling load can then be found for a range of
enthalpies for each ventilator.
EXAMPLE: The design dry bulb temperature for Miami is 90_F
and the average wet bulb at that temperature is 77_F. Using the
psychrometric chart, the enthalpy is about 40.5 Btu per pound
(Btu/lb) of dry air, which would round up to 41 Btu/lb dry air. In
the left column, at 41 Btu/lb dry air, the ERVBBLHA1200 has an
additional cooling load of 5042 Btuh, while the HRV1150CFM
unit has an additional cooling load of 8437 Btuh.
6
BEDROOMS
4---5 6---7 >7
28 35 42
35 42 50
42 50 57
50 57 64
57 64 71
64 71 78
HRV1150 HRV1250
640 670 1071
1090 1741
1509 2411
1928 3080
2347 3750
2766 4419
3185 5089
3604 5759
4023 6428
4442 7098
4861 7767
5280 8437
5699 9107