# Resources

## Software Resources

The following software is available for ThermalNetics customers. Please contact us for access.

**Daikin Applied **

- Energy Analyzer
- Acoustic Analyzer
- Pipe Sizer
- Duct Sizer
- Daikin Tools for Engineers Selection Software

**Neptronic**

**Enviro-Tec**

**Lennox**

## Commonly Used HVAC Formulae and Conversions

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**Air Side**

Q_{Total} = CFM x (h_{i} - h_{f}) x 4.5 Btuh

Q_{Sensible} = CFM x (t_{i} - t_{f}) x 1.085 Btuh

Q_{Latent} = CFM x (Gr_{i} - Gr_{f}) x .068 Btuh

Humidification = CFM x (Gr_{f} - Gr_{i}) / 1,555 lbs/hr

CFM = l/s x 2.12

Air Pressure Drop (in. wg) = Pa / 249

**Water Side**

Q = USGPM x (t_{i} - t_{f}) x 500 Btuh

Q = USGPM x (t_{i} - t_{f}) x 450 Btuh (50% E.G.)

Q = USGPM x (t_{i} - t_{f}) / 24 Tons

USGPM = l/s x 15.85

Water Pressure Drop (ft. wg) = kPa x 0.335

1.0 PSI = 2.31 wg

7,000 Grains = 1.0 lb

**Miscellaneous**

**1.0 Ton** = 12 MBH = 12,000 Btuh

**1.0 Therm** = 100,000 Btuh = 100 MBH

**COP** = 3.516 / (kw / Ton)

**EER** = Tons x 12 / (Total kW input)

**Btuh** = Watt x 3.412

**HP** = kW x 1.3405

**1 Boiler HP** = 33.48 MBH

**1 US Gallon** = 8.33lbs

**Latent heat of vaporization of steam in air** (average) = 1,050 Btuh/lb

**The Affinity Laws (Fan/Pump Laws)**

`text(rpm)_(2)/text(rpm)_(1)=text(Flow)_(2)/text(Flow)_(1)`

`(DeltaP_(2))/(DeltaP_(1))=(text(Flow)_(2)/text(Flow)_(1))^(2)`

`"mhp"_2/"mhp"_1=("Flow"_2/"Flow"_1)^3`

`"Pump BHP"= ("USGPM " xx " Head (ft. wg)")/("3960 "xx" Pump Efficiency")`

`"Fan BHP"= ("CFM " xx " S.P. (inches wg)")/("6356 "xx" Static Efficiency")`

**Air-Conditioning Formulas**

**1 Btu** = amount of heat required to raise or lower temperature of one pound of water 1°F

**1 ton refrigeration** = 12,000 Btu/h = 200 Btu/min

**1 watt** = 3.412 Btu/h

**1 horsepower** = 2545 Btu/h

**1 lb** = 7000 grains

**1 ft (head)** = 0.433 psi

**1 square foot EDR** (equivalent direct radiation) = 240 Btu

**1 boiler horsepower** = 33,479 Btu/h

**No. of air changes** (*N*) =60 cfm/ft^{3}

**Sensible heat** (Btu/h) = 1.08 `QDeltat`

Where `Deltat` = difference between entering and leaving dry-bulb temperature and `Q` = airflow rate in cubic feet per minute

**Latent heat** (Btu/h) = 0.68 `QDeltag`

Where `Deltag` = difference in moisture content of entering and leaving air, grains per pound of dry air

**Water quantity** (gpm) required for heating and cooling = q/500 `Deltat_(water)`

Where q = load in Btu/h

**Chiller capacity** (tons) = `"gpm (chilled water) " xx (Deltat_(water))/24`

**For air:**

1 lb/h = 4.5 *Q*

1 ton = `(QDeltah)/2670`

Fan HP = `("cfm " xx " static pressure" " (in. w.g.)")/("6356 " xx " Efficiency")xx"Density of air"/"Density of standard air"`

Small fans 0.40 – 0.50 efficiency

Large fan 0.55 – 0.60 efficiency

**For water:**

1 lb/h = 500 gpm

1 ton = (gpm) `(Deltat)/24`

Pump HP = `("gpm " xx " ft head")/("3960 " xx " Efficiency")xx" Specific gravity"`

Small pumps 0.40 – 0.60 efficiency

Large pumps 0.70 – 0.85 efficiency