## Water heater recovery rate calculation

Calculate the amount of time it takes to heat the water by dividing the power used to heat the water, which was determined to be 1.867 with the heater element rating, listed in kW. So if your heater element rating was 3.6 kW, your equation would look like this: heating time = 1.867 ÷ 3.6, or heating time =0.52 hours.

Therefore, to size a demand water heater, you need to determine the flow rate and Additional calculations involved in sizing your solar water heating system  Domestic Hot-Water sizing equations - heating capacity, recovery rate and power supply. 1 Oct 2009 It's expressed in gallons per hour. Typical 50-gal. water heaters will have recovery rates in the range of 40 gph, but there are heavy-duty models  What is Recovery Rate? Answer Recovery rate is the amount of hot water the water heater is capable of providing in a given period of time, not to be confused with first hour rating, which includes recovery rate plus 70 percent of the tank capacity(see FAQ #8).The amount of hot water provided will depend on several things. Recovery rate is the amount of water, expressed in gallons per hour (GPH),heated to a given temperature the draw efﬁ ciency and gallon capacity of the water heater may be used to calculate the length of the showering period in minutes. … Example: If the water heater is 40 gallons with a 36,000 BTU burner you take; 40 (gallons) x .7 + 49.9 (GPH at 50 degree rise in temp — make sure you figure on winter water temps) = 77.9 gallons first hour rating. For example, if you have a 30 gallon water heater, and you run the dishwasher, wash clothes and have a long shower, you will drain the water heater completely of hot water. This means that if the unit has a recovery rate of 29 gallons, your water heater will be refilled almost completely within an hour of waiting.

## What is Recovery Rate? Answer Recovery rate is the amount of hot water the water heater is capable of providing in a given period of time, not to be confused with first hour rating, which includes recovery rate plus 70 percent of the tank capacity(see FAQ #8).The amount of hot water provided will depend on several things.

Recovery rate is the amount of water, expressed in gallons per hour (GPH),heated to a given temperature the draw efﬁ ciency and gallon capacity of the water heater may be used to calculate the length of the showering period in minutes. … Example: If the water heater is 40 gallons with a 36,000 BTU burner you take; 40 (gallons) x .7 + 49.9 (GPH at 50 degree rise in temp — make sure you figure on winter water temps) = 77.9 gallons first hour rating. For example, if you have a 30 gallon water heater, and you run the dishwasher, wash clothes and have a long shower, you will drain the water heater completely of hot water. This means that if the unit has a recovery rate of 29 gallons, your water heater will be refilled almost completely within an hour of waiting. However it can be used to calculate general hot water recovery time for any amount of water. If you would like the ability to select higher KW amounts please either feel free to get in touch and tell us or use the formula to calculate it. Volume is the amount of water you wish to heat up this is in litres.

### 1 Oct 2009 It's expressed in gallons per hour. Typical 50-gal. water heaters will have recovery rates in the range of 40 gph, but there are heavy-duty models

Therefore, to size a demand water heater, you need to determine the flow rate and Additional calculations involved in sizing your solar water heating system  Domestic Hot-Water sizing equations - heating capacity, recovery rate and power supply. 1 Oct 2009 It's expressed in gallons per hour. Typical 50-gal. water heaters will have recovery rates in the range of 40 gph, but there are heavy-duty models  What is Recovery Rate? Answer Recovery rate is the amount of hot water the water heater is capable of providing in a given period of time, not to be confused with first hour rating, which includes recovery rate plus 70 percent of the tank capacity(see FAQ #8).The amount of hot water provided will depend on several things. Recovery rate is the amount of water, expressed in gallons per hour (GPH),heated to a given temperature the draw efﬁ ciency and gallon capacity of the water heater may be used to calculate the length of the showering period in minutes. …

### Gas water heater recovery table (calculated at 75% recovery efficiency). GALLONS STORAGE +HEAT INPUT = WATER AVAILABLE TO MEET USAGE FACTORS These design factors are the result of combining A.O. Smith engineering test data and practical experience to form a usable guide for the selection of minimum water heater tank sizes and heat inputs.

For example, if you have a 30 gallon water heater, and you run the dishwasher, wash clothes and have a long shower, you will drain the water heater completely of hot water. This means that if the unit has a recovery rate of 29 gallons, your water heater will be refilled almost completely within an hour of waiting. However it can be used to calculate general hot water recovery time for any amount of water. If you would like the ability to select higher KW amounts please either feel free to get in touch and tell us or use the formula to calculate it. Volume is the amount of water you wish to heat up this is in litres. For example, if you have a large household and you use a lot of hot water at once, the recovery rate should be at least equal to the size of your water heater. So, a 60-gallon water heater should have a recovery rate of at least 60-gallons. For an electric water heater, the RE is 100%. For gas water heaters the conversion rate is typically 76-78%, with expensive high efficiency units reaching 94%. This is because some energy must be left in the combustion byproducts to assure good venting." http://energyexperts.org/EnergySolutionsDatabase/ResourceDetail.aspx?id=594 Recovery rate for an electrical heater in a domestic hot water system: RR = h in μ / dt ρ = P (3413 Btu/kW) / dt ρ (3) RR = recovery rate (gal/h) Gas water heater recovery table (calculated at 75% recovery efficiency). GALLONS STORAGE +HEAT INPUT = WATER AVAILABLE TO MEET USAGE FACTORS These design factors are the result of combining A.O. Smith engineering test data and practical experience to form a usable guide for the selection of minimum water heater tank sizes and heat inputs. The flow rate through the demand water heater would need to be at least 3.25 gallons (12.3 liters) per minute. To reduce flow rates, install low-flow water fixtures. To determine temperature rise, subtract the incoming water temperature from the desired output temperature.

## Typical 50-gal. water heaters will have recovery rates in the range of 40 gph, but there are heavy-duty models that go as high as 50 to 60 gph. There are also a few companies, such as Bock Water Heaters, with residential products that have powerful burners which enable very high recovery rates (142 to 159 gph).

Recovery rate is the amount of water, expressed in gallons per hour (GPH),heated to a given temperature the draw efﬁ ciency and gallon capacity of the water heater may be used to calculate the length of the showering period in minutes. … Example: If the water heater is 40 gallons with a 36,000 BTU burner you take; 40 (gallons) x .7 + 49.9 (GPH at 50 degree rise in temp — make sure you figure on winter water temps) = 77.9 gallons first hour rating. For example, if you have a 30 gallon water heater, and you run the dishwasher, wash clothes and have a long shower, you will drain the water heater completely of hot water. This means that if the unit has a recovery rate of 29 gallons, your water heater will be refilled almost completely within an hour of waiting. However it can be used to calculate general hot water recovery time for any amount of water. If you would like the ability to select higher KW amounts please either feel free to get in touch and tell us or use the formula to calculate it. Volume is the amount of water you wish to heat up this is in litres. For example, if you have a large household and you use a lot of hot water at once, the recovery rate should be at least equal to the size of your water heater. So, a 60-gallon water heater should have a recovery rate of at least 60-gallons. For an electric water heater, the RE is 100%. For gas water heaters the conversion rate is typically 76-78%, with expensive high efficiency units reaching 94%. This is because some energy must be left in the combustion byproducts to assure good venting." http://energyexperts.org/EnergySolutionsDatabase/ResourceDetail.aspx?id=594

However it can be used to calculate general hot water recovery time for any amount of water. If you would like the ability to select higher KW amounts please either feel free to get in touch and tell us or use the formula to calculate it. Volume is the amount of water you wish to heat up this is in litres.