Bryant HEAT RECOVERY VENTILATOR HRVBBLHA - Manual (Page 6)

6
METHOD TO SIZE ERVs and HRVs
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
AREA (ft 2 )
BEDROOMS
0---1 2---3 4---5 6---7 >7
<1500 30 45 60 75 90
1501---3000 45 60 75 90 105
3001---4500 60 75 90 105 120
4501---6000 75 90 105 120 135
6001---7500 90 105 120 135 150
>7500 105 120 135 150 165
Table 2 – Ventilation Air Requirements, L/s
FLOOR
AREA (m 2 )
BEDROOMS
0---1 2---3 4---5 6---7 >7
<139 14 21 28 35 42
139.1---279 21 28 35 42 50
279.1---418 28 35 42 50 57
418.1---557 35 42 50 57 64
557.1---697 42 50 57 64 71
>697 50 57 64 71 78
HEATING AND COOLING LOAD CHARTS
Although the ventilators process the outside air before it enters the home, additional heating and cooling loads need to be considered.
HEATING LOAD BTUH
Outside
Temp °F
Heating Load (Btuh) @
Inside Design Temp 72°F
ERV1150 ERV1200 HRV1150 HRV1250
–25 5186 8143 6636 10603
–20 4919 7723 6294 10057
–15 5075 7967 5952 9510
–10 4783 7509 5610 8964
–5 4491 7051 5268 8417
0 4200 6594 4925 7871
5 4234 6647 4583 7324
10 3918 6151 4241 6777
15 3958 6214 3899 6231
20 3611 5669 3557 5684
25 3264 5124 3215 5138
30 2916 4579 2873 4591
35 2569 4034 2531 4045
40 2222 3489 2189 3498
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.
COOLING LOAD BTUH
Outside
Enthalpy
Btu/lb
Cooling Load (Btuh) @ Inside Design Temp
72°F and 50% Relative Humidity
ERV1150 ERV1200 HRV1150 HRV1250
30 380 640 670 1071
31 618 1040 1090 1741
32 855 1441 1509 2411
33 1093 1841 1928 3080
34 1331 2241 2347 3750
35 1568 2641 2766 4419
36 1806 3041 3185 5089
37 2043 3441 3604 5759
38 2281 3842 4023 6428
39 2519 4242 4442 7098
40 2756 4642 4861 7767
41 2994 5042 5280 8437
42 3231 5442 5699 9107
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.
ER
V
/HR
V