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Often, energy is measured in kWhs 180 litres of water is near enough 180kg. Hi “New pool, cold water !” The two keys they had were that it cost \$0.51 to heat 40 gallons using gas or \$0.73 using electric. Fill in your details below or click an icon to log in: You are commenting using your WordPress.com account. Change ), heating elements, immersion heaters, and more, Watt density and its importance for brewery immersion heaters. I have saved the page to my home screen. One Btu is 0.000293 kWh. Running a bath will use approximately 60 - 80 litres of water. To boil ALL the water: What formula did you use to calculate the water heating power? There are many other factors including the temperature of the cold water entering the heater system, the temperature of the hot water coming out of the heater and hot taps and the cost per kWh of the energy. that is impossible to calculate with the information given. Heating water to have a bath can be a major cost on your energy bills depending on how you heat the water and how much water you use. A litre of water at 25℃ needs a certain amount of calories to become steam at 100℃ ∆t=75℃ (75Kcal + 540Kcal =615Kcal) if I remember the figures. E = (4.2 kJ/kgoC) ( (90 oC) - (20 oC)) (1000 liter) (1 kg/liter) = 294000 kJ. Heating water to have a bath can be a major cost on your energy bills depending on how you heat the water and how much water you use. It would be really cool to see a calculator that takes this new technology into account. But when the state of water changes from solid to fluid (e.g. The higher element usually is for when you need to heat some water in middle of day. Heat capacity formula. Cost To Heat Water Using Electricity A typical electric water heater is 90.4 to 95% efficient or 92.7% average efficiency. The answer was 4 hours. is this calculation valid only when submerging the heating device in the water, or also when the water is circulating through a heating pipe using a pump? Heating oil provides 138,500 British thermal units (BTU) per US gallon; 1 BTU = 0.000293 kWh; 1 US gallon = 3.78541178 litres (138,500 * 0.000293)kWh in 3.78541178 litres (138,500 * 0.000293)/3.78541178 kWh/litre = 10.720233982047786621512547837002 With a 3 hour design reheat time, this means a power input of about 2600 watts. This kind of thermal radiation is similar to feeling the heat of a campfire on your face from a distance. 1 litre of water has a mass of 1 kg. It is the way it is taught at school. 1758120 kilojoule/hour = 488.36666667 kilowatt hour A BTU is the amount of energy required to heat 1 pound of water by 1°F (specifically from 39° to 40°F). The specific heat capacity of water is approx 4.2 J / g.K. Here’s a breakdown of how hot water is used in an average month. How much heat energy in joules is necessary to raise the temperature Of 7000 kg (7 M3) of water from 20 °C to 80 °C? I want to convert this to Watthours but I'm not sure how....does bringing time into the equation determine how much energy I need to expend? The cost of electricity is for example 7.15 €ct per kWh and for natural gas is 28 €ct per m 3 of gas. 100 kcal of heat is required to raise the temp of 1 kg water from 0 ˚C to 100 ˚C. I'm heating a liter of water from 25C to 60C. The calculators cannot handle points or commans, only whole numbers. Start temp as final and end temp as start. At \$0.11/kWh, it costs 6.63 x \$0.11 = \$0.73 to heat a 40-gallon tank." 1 litre of water is 1kg 1 meter cube = 1000 Ltrs M = 7 meter cube = 7000 Ltrs or 7000 Kg The heat capacity Cp of water is 4.186kJ/kg-C ΔT = 80-20 = 60 C annual and total lifetime water heating costs based on different water heating systems and energy sources. I’m looking at a 50,000 btu boiler with a heat exchanger to heat a 33,000 gallon pool to 90 degrees f. I’ve run then calculation through the formula above, and it’s coming up with a 600,000 btu boiler to raise the water temp (68f) in 5 hours to 90f, which seems to be a really high number? I am looking for how much energy is need to maintain water temperature. It makes 1 out of 1.6, excellent piece of kit. All help is greatly appreciated - where possible, assume 'normal' conditions, i.e., use a standard or generally accepted density for air. So 78 C rise requires 326,508 Joules per kg. That means that for every 10 litres of hot water you use will only cost you 7 cents. (U.C. Let’s make a calculation example for a tub with 250 us gallons that cools down from 105f to 103f in 2 hours. I’m curious, though. Converesely, if we only use half the heating power, 1.75kW, it will take twice as long to heat up to desired temperature, ie, 2 hours. They are also measured by heat content. Your calculators are a big help in figuring the size of the heat sump. The following formula is used to calculate the power of heating element needed to heat a specific volume of water by a given temperature rise in 1 hour. how to calculate power required to heat water. An I missing something here? If we only have a 1kW element available, we will expect a heat up time in excess of 3 hours. This is the typical heat capacity of water. Change ), You are commenting using your Google account. Volume of fluid to heat in litres: Starting temperature degrees C: Target temperature (finishing) degrees C: Heating power kW: Density of water kg/dm 3: 1. time required to reach target temperature at given power: hours Specific Heat Capacity: 4200 J / kg / C This is a measure of the amount of energy, measured in Joules, required to heat water. Specific heat capacity of water kcal/kgx°C 3: 1. The calculators assume 100% efficiency and no loss of energy during the heating process. As for efficiency, an electrical water heater can convert electricity with almost 100% efficiency to heat that can be transferred to the water. Specific heat capacity of water kcal/kgx°C 3: 1. For that reason, these values are the minimum and some margin should be added to them. 98°C to 102°C) this does not hold true any more. The calculators use the specific heat capacity of water of 4186 J/kg/°C (Joules per kilogram per degree Celsius). Straight to the point. meaning that the water would be heated in 1 hour by 3.5kW of applied heat. Using the “Water Heating Power Calculator” above (250 us gallons, start temperature 103f, end temperature 105f, 120min) tells us that a heating power of 611 watts is required. Heating a full 184 litre (40g) tank costs \$1.33 and \$2.01 for a 279 litre (60g) tank. 1kcal=1000cal. And 1 calorie equals 4,184 Joule. The heat capacity Cp of water is 4.186kJ/kg-C ( Log Out /  Improved calculators that support comma, dot, and efficiency, are available here: time, energy, and power. Hi, I am trying to calculate the energy required to heat air that is 6.7 degrees C to 21 degrees C, in kilowatt hours, and for a range of other temperatures (5.7, 6.9, 9.5..... and many others, all to 21 degrees celsius/centigrade). The calculators cannot deal with dots or comma. Is that realistic? So one Btu is 0.00001 therms. The amount of energy needed to raise the temperature of 1 g of water by 1 degree Celcius or (1 Kelvin) equals 1 calorie. Heating a gallon of water by 1°F with no losses thus takes 8.33 lbs x 1 Btu/lb = 8.33 Btu's. One kilo calorie is the amount of heat needed to raise the temp. Change ), You are commenting using your Facebook account. If you can test how fast the water cools down in your tub, then you can calculate how much heating power is required to prevent that from happening. Please remember, that the calculators above assume 100% conversion efficiency. This means that you will have to pay 23 €ct to heat the bathwater with electricity and and 12 €ct to heath with gas if you take a bath (exlusive watercosts). Running a bath will use approximately 60 - 80 litres of water. While this appears to be a conservative estimate of water-related energy use, our findings suggest that the carbon footprint currently associated with moving, treating and heating water in the U.S. is at least 290 million Roughly speaking, due to its density and viscosity, heavy oil will heat up in half the time of water, or if you prefer, require around half the heating power to heat up the same volume of water in the same period of time. Last edited: Jun 16, 2016. How to calculate the kW required to heat a volume of water in a particular time. K). Formula to calculate electricity or gas consumption of water heating . How long would it take a kettle with a 1kW heating element to heat 1 litre of water? Example - Batch Heating with Steam . Thats \$0.01275 per gallon for gas and \$0.01825 per gallon with electric. I just want to maintain the temperature. Energy rates as of November 1, 2020. for example 100 litres of water, to be heated from 20 ºC to 50 ºC, giving a temperature rise of 30 ºC would give – 100 x 4 x 30 / 3412 = 3.52 meaning that the water would be heated in 1 hour by 3.5kW of applied heat. One therm is 100,000 btu's. density of water is 1g/cu.cm or 1kg/cu.d. 566 Btu's x 0.000293 kWh/Btu = 0.166 kWh. … This is great. Posted on March 13th, 2016 Great help to calculate water flow and energy consumption! The answer is 6 hours 24 minutes. It would be more complicated to build calculators that can handle that and I have not done so. To heat the same water volume in half the time (30 minutes) would need twice the heating power, ie, 7kW. Calculate the kilowatt-hours (kWh) required to heat the water using the following formula: Pt = (4.2 × L × T) ÷ 3600. I do not think it makes much of a difference in practice. One kWh is 3413 Btu's, so one Btu is 1/3413 = 0.000293 kWh. Change ), You are commenting using your Twitter account. Also, the calculator is only correct in the theoretical case that while the water is being heated, no heat escapes from the water to the environment (air or walls etc.). specific heat of steam is 2.1 kJ/kgK. A Watt is named after James Watt hence the abbreviation is a capital W. A thousand of something is a “kilo” for example a kilogram. natural gas, or kilowatt hours or electricity (kWh). Let's call that 92.7% on average. This calculator is great. The gas needed depends on your boiler, it's perhaps 60% efficient. I entered 688 litres start temperature 29 C end temp 37 C with 1600 watts of power. This was super helpful in calculating the power needed to produce my hot water via solar photovoltaics. Water is heated to 90oC. 1 L water = 0.998 kg. Hot water immersion heater elements are usually rated at 3 or 6 Kilowatts (kW). EDIT: My gas is billed in 15kg gas cylinders, but feel free to allow for liters of gas. The increase in temperature is 45 Kelvin (60-15) So the energy needed is 180,000 x 45 x 4.2 = 34MJ. Now, 1 kWh contains 3.6 MJ/kWh. This is also The value of the specefic heat of water. The surrounding temperature (where the energy can be transferred to) is 20oC. specific heat of ice is 2.06 kJ/kgC. I'm under the impression that a Calorie (kcal) heats one liter of water by one degree, and so heating one liter by 35 degrees requires 35 Calories. I'm heating a liter of water from 25C to 60C. With a 3 hour design reheat time, this means a power input of about 2600 watts. M = 7 meter cube = 7000 Ltrs or 7000 Kg Wouldn’t it be faster in the latter case, because the water flow would exchange heat more efficiently than just by convection? it takes the same amount of energy to heat water from 48 degrees to 52 degrees as it takes to heat water from 58 degrees to 62. According to "latent heat of vaporization of water" it would take around 0.62 kWh/liter but I'm not sure...please help! So it takes 525 ÷ 92.7% = 566 Btu's to heat a gallon of water in an electric tank. ie, the metal kettle on the gas hob, would loose more water temperature, than say the plastic, electric kettle, as plastic is a better heat retainer than metal. or = 488 .36 KW ( Log Out /  Click HERE for our online water heat up time calculation page. The cost of electricity is for example 7.15 €ct per kWh and for natural gas is 28 €ct per m 3 of gas. Also we can use this formula as the basis of similar calculations for heating oil. Thus,mass of 1l water=1kg. Save my name, email, and website in this browser for the next time I comment. To heat 1 ml of water takes 4.18 Joules per degree C, the specific heat capacity. They are saying the modern heat pumps can give you 3.8 watts worth of hot water (or something close to that) for each watt that the heat pump uses. Calculation for working out factor to convert litres of heating oil into kWh / litre. 1 to heath one liter of water … For an electrical heater that can be a good assumption, but not for a gas heater. Water at room temperature 22 C must be raised to 100 C and heat of vaporisation added to become a gas. Over an hour it would be “kWh”. Density: 1000 kg / m 3 or 1 kg / litre This is a measure of the mass (weight) of a set volume of water. Boil or evaporate? @Anna Thermal radiation losses are responsible for 20%-30% of heat energy loss in the swimming pool. The higher element usually is for when you need to heat some water in middle of day. I'm looking for the same calculation, but for gas. To heat the water to boiling: E = 4.186 kJ/kgC x 0.998 kg x 76C = 317.5 kJ = 0.088 kW-hr. I’m trying to figure out what would it take to heat my pool using a heating pipe after the filtration pump. The insulation of where the heating device sits and whether any heat can escape into something other than the water (like a wall, concrete etc.) There's a great answer about heating water with electricity, where anyone can easily get an idea how much would it cost to heat water just by applying one's price for kWh. At Process Heating Services, we have 2 types of customer. ( Log Out /  This calulator tells you how much minimum heating power is required to heat the water within a specified amount of time. 1000 watts is 1000 Joules per second, but spread over 1000 ml. One kWh is 3413 Btu’s. 1 BTU is the amount of heat required to raise the temperature of 1 pound of water 1 degree F. (1 kg x 1 degree C would be 3.96 BTU.) 1kWh = 1000W x 3600s = 3.6MJ. Volume of fluid to heat in litres: Starting temperature degrees C: Target temperature (finishing) degrees C: Heating power kW: Density of water kg/dm 3: 1. time required to reach target temperature at given power: hours There are many other factors including the temperature of the cold water entering the heater system, the temperature of the hot water coming out of the heater and hot taps and the cost per kWh of the energy. Hi all. specific heat of water is 4.186 kJ/kgC. So if you want to raise the temperature of 1 litre of water (1 litre = 1000g for water) by 80 degrees Celcius, your calculation should look like this: 1000g*4,184J/ (g*°C)*80°C= 334 720 Joules 1 kWh = 3 600 000 Joules, because 1 watt of power during 1 second equals 1 Joule. Only input whole numbers, do not use a comma or point. Calculation for working out factor to convert litres of heating oil into kWh / litre. When using a simple coil submerged in water, then it will start to heat the water just around it. I am wondering though, doesn’t heat capacity increase with temperature, potentially throwing off the calculation? Appreciate the calculators but i was wondering if you could tell me the exact equations used for the “Water Heating Energy Calculator” or give some sort of excel sheet to double check it. The specific heat of water is 4186 Joules/kg-C. As such, for every litre of hot water, you need to factor in: the price of a litre of water; the write-off of the purchase price and the installation cost of your domestic hot water generating system; your energy consumption to heat this litre of water. This is the typical heat capacity of water. Irvine) Heating a gallon of water by 1°F with no losses thus takes 8.33 ÷ 100,000 = 0.00008.33 therms. You used 0.001163 of one kilowatt-hour to heat your liter of water from 0°C to 1°C. I just recently learned about hybrid heat pump water heaters for the home that have much higher heating efficiency than standard electric. If you want to boil it and turn it all completely into steam, you'll need another 0.7421 kilowatt-hour As 1 litre of water needs about 1.16 watts to raise it through 1°C in an hour, a 120 litre tank of cold mains water needs a total energy input of about 7800 watts-hours (120*1.16*56) to raise its temperature to the required level. The energy stored in the water tank can be calculated as. 3412 BTU = 1 kWh. Water Litre to kg: 1 Litre = 0.999975 kg, so for all practical purposes 1 L = 1 kg Water kg to Litre: 1 kg = 1 litre Example: LPG Gas 14.2 kg Equals How Many Liters with 75% Butane For LPG (propane) 1 kg = 1.96 L. Therefore, 14.2 kg = 27.832 L. For LPG (butane) 1 kg = 1.724 L. Therefore, 14.2 kg = 24.48 L In turn the abbreviation, for one thousand, is k. Bringing these two together, a kilowatt is a “kW”, not as you have, “Kw”. For Heating Water in Tanks: KW = Liters x Temperature Rise (°C) 790 x Heat-up Time (hrs.) Labels: energy savings, math. At \$1.20 /therm, it costs 11.31 x \$1.20 = \$13.58 to heat 1000 gallons. One gallon of gasoline (petrol) is about 118,000 BTU. C p is the specific heat of water (4.186 J/gm deg C) The calculator below can be used to determine the temperature delta or rise for a given cooling water application (heat load or power dissipated and cooling water flow rate) using the first formula above. For 4 hours 488/4 = 122kw Think of power as the rate at which energy is used. At \$1.20 /therm, it costs 11.31 x \$1.20 = \$13.58 to heat 1000 gallons. The power in watts is then found by: energy (joules) / time (seconds) To convert that answer to kilowatts, divide by 1000. A kilocalorie (C) is the amount of energy needed to heat 1 liter (1000 milliliters or 1000 cubic centimeters) of water one degree centigrade. Thank you. If we can calculate the volume of water and the required temperaure rise, we can answer this question. Cost To Heat Water Using Electricity A typical electric water heater is 90.4 to 95% efficient or 92.7% average efficiency. 1 litre for 1 degree in 1hour is 1,16 kW/h. One calorie is the amount of heat needed to raise the temp. ( Log Out /  L is the number of liters of water that is being heated and T is the difference in temperature from what you started with, listed in degrees Celsius. There are others who need guidance and advice as to what they need. A simple formula to estimate the energy required to heat a volume of water is : E = C*V*DeltaT/PR Where E = energy in kWh C = Specific heat of water - 4.187 kJ/kgK, or 1,163 Wh/kg°C V = volume of water to heat deltaT = Th-Tc Th = temperature of hot water Often, energy is measured in kWhs A 60 watt light bulb uses 60 watt-hours of energy in one hour. Sweet! I am assuming calculations take into account the specific heat capacity of water? I’ve been looking for a simple way to ballpark the size of a solar thermal hot water system – and this makes it dead simple! This means that you will have to pay 23 €ct to heat the bathwater with electricity and and 12 €ct to heath with gas if you take a bath (exlusive watercosts). At \$0.30/kWh that's \$2.85. The volume in gallons (5), ambient temperature (46F) and target temperature (161) are variables that will change. In the United States, the most commonly used value for expressing the energy value or heat content of a fuel is the British thermal unit (Btu). It very much depends on the surrounding temperature, the heat conductivity of your hot tub material, and the shape of the tub. is more important for efficiency. If you use a 611 watts heater in this example, then it will be about enough to reverse this cool-down from 105f to 103f by heating the water back up from 103f to 105f during the same period (realistically, of course, the water does not cool down, but stays at the same temperature). I think of it this way: the power limit of heating coil simply submerged in water is reached when the water starts to boil around the coil while the water in other places is still much colder. If i change the power to 1.6kw . The heat capacity is largely constant in the temperature range that the calculators work (34-210°F or 1-99°C). There's a great answer about heating water with electricity, where anyone can easily get an idea how much would it cost to heat water just by applying one's price for kWh. Also we can use this information to extrapolate both ways. Hot water cylinders/tanks come in many shapes, sizes and capacities, ranging from 40 to over 400+ litres in larger homes. Also we can use this information to extrapolate both ways. And this is 488.36 Kilo Watts of power (since 1J/s = 1W) Specific Heat Capacity: 4200 J / kg / C This is a measure of the amount of energy, measured in Joules, required to heat water. This calculator tells how much energy will be consumed to heat the water from the start to end temperature. How much depends on the shape of your pool, the quality of the insulation of the pool, the difference of the desired water temperature to the environment and how long you are willing to wait until it is heated. A typical electric water heater is 90.4 to 95% efficient. Create a free website or blog at WordPress.com. However, oil needs a much lower watts density element than water, as described in the “How to choose an oil heater” article. volume in litres x 4  x temperature rise in degrees centigrade / 3412, (4 being a factor and 3412 being a given constant), for example 100 litres of water, to be heated from 20ºC to 50ºC, giving a temperature rise of 30ºC would give –. It takes 667 92.7% = 720 Btu’s to heat a gallon of water using electricity. One Btu is 0.000293 kWh. For 8 hours 488/8 = 61kw. of 1kg water by 1˚C . I am tasked to maintain a 110L aquarium at 22-24C outdoors in Texas. Thank you! 488 kwh for 1 hour 1 Watt = 1 Joule of energy per second 1 kW = 1000 Joules of energy per second. Hence, the energy needed is 34/3.6 = 9.5 kWh. That’s just an example, I have no idea how fast a tub cools down. -2°C to + 2°C) or from fluid to gas (e.g. Under partial vacuum, such energy requierement can be less. P = calculated heat transfer (kW) h e = evaporation energy of the steam (kJ/kg) The evaporation energy at different steam pressures can be found in the Steam Table with SI Units or in the Steam Table with Imperial Units. So, the energy required to raise the temperature of 7000 kg of water from 20C to 80C is: I am guessing its q=m*cp*dt but when I do the calcs by hand, i get something off so i would like to know my mistake, How much heat energy in joules is necessary to raise the temperature Of 7000 kg (7 M3) of water from 20 °C to 80 °C? As for effectiveness, a large enough pipe with a pump can probably in theory transfer more heat per second (meaning power, e.g. Solve for Thermal Power For rocket science one might want to calcualte it more accurately. Lecci is about 10p / kWh, so about 50p for a bath and 10p for a litre of tea. For practical purposes, it should be precise enough. Hot water immersion heater elements are usually rated at 3 or 6 Kilowatts (kW). It takes 667 92.7% = 720 Btu’s to heat a gallon of water using electricity. Hot water cylinders/tanks come in many shapes, sizes and capacities, ranging from 40 to over 400+ litres in larger homes. How do I calculate btu size for heating a swimming pool? Pt is the power used to heat the water, in kWh. Generally, oil heats up in half the time of water, due to its density. meaning that the water would be heated in 1 hour by 3.5kW of applied heat. I'm looking for the same calculation, but for gas. This is the best set of calculators on the internet . This is why the calculators complain in these situations. EDIT: My gas is billed in 15kg gas cylinders, but feel free to allow for liters of gas. Our updated website is up, running and ready for viewing. It depends how much you want to heat the water up by: As a general rule, the energy (in joules) to heat water is given by: Energy = mass of water (kg) x temperature rise (celsius) x 4200. And as always, double check with some other source and my help is without any guarantee or similar. One kWh is 3413 Btu’s. I have done the calculations in the calculator above for heating 33’000 US gallons from 68F to 90F in 5h (300min) and got a result of approximately 1’200’000 btuh. For less than the price of a new heater tank, I now have free hot water. That is a 1 ATM. But I have an idea. If you have problems with the units, feel free to use our temperature conversion or weight conversion calculators. of 1g water by 1˚C . 1 kilowatt hour (kWh) = 3.6 megajoules 1 megawatt hour (MWh) = 3.6 gigajoules 1 kJ = 0.278 Wh 1 MJ = 0.278 kWh 1 GJ = 278 kWh 1 TJ = 278 MWh 1 PJ = 278 GWh 1 kWh = 3.60 MJ 1 calorie (c) = 4.19002 Joules Note 1 calorie is (approximately) the amount of heat required to raise the temperature of one ml of water by 1 degree Celsius. Thanks! 1 C. colshaws. To determine BTU lost can I use the “Water Heating Energy Calculator” only backwards? ΔT = 80-20 = 60 C Last updated on April 16th, 2020. is there a formula to calculate the temperature required for 5 gallons of water that will increase the temperature of a stainless steel 15.5 gallon tank from 46F to 161F. Since water gets lighter when heated it will start to ascend around the coil and cold water will flow to the coil from below. Also, you should have some extra power available, just to be sure. Gas Engineer. 1 to heath one liter of water it will cost one kcal, what equals 4.18 kJ. So they may complain when you input commas or points. If using electric it's near enough 100% energy conversion from energy paid for to heat, but leccie is more expensive than gas per kWh (see bills). Cost of 1 litre of hot water according to appliance type . Density: 1000 kg / m 3 or 1 kg / litre This is a measure of the mass (weight) of a set volume of water. water-related energy use is at least 521 million MWh a year—equivalent to 13% of the nation’s electricity consumption. Time period available to heat the water (minutes), Water Heating Calculator for Time, Energy, and Power. = (294000 kWs) (1/3600 h/s) = 81.7 kWh. Problems with limit calculations: It complains if the end temp is 212°F or even 211°F, saying it must be less than boiling. For Heating Water in Tanks: KW = Liters x Temperature Rise (°C) 790 x Heat-up Time (hrs.) The calculators support Celcius/Centigrade, Fahrenheit, Watts (w), Kilowatts (Kw), Btuh, Joule, British termal unit (Btu), liter, gallon, kg, lb, cubic inch, cubic foot etc. 1 litre of water is 1kg Your immersion could be slightly faulty, or be covered with scale in some hard water areas . Nice calculator buttt…… you’ve got the abbreviations for the metric units incorrect. Hi Larry, the energy that is used to heat water from 40 degrees to 60 is the same amount that is lost when the water cools down from 60 to 40 (only changed sign). Also we can use this information to extrapolate both ways. To heat the same water volume in half the time (30 minutes) would need twice the heating power, ie, 7kW. So we've got 0.166 kWh to heat a gallon of water, or 0.166 x 40 = 6.63 kWh to heat a 40-gallon tank. , As another calculator for us math dummies could be total kw x cost of electrical supply. And for testing/sampling the cool-down, measure a larger drop in temperature, such as 10f, else the result will be unreliable (reading 1f or 2f changes off a small thermometer may be very inaccurate). The mass of the one liter of H2 produced by a typical "HHO" scam device in one minute: .000089 kg = .089 grams = 89 milligrams. Thermal radiation losses occur from direct sunlight, high water temperature or high relative humidity. heat of fusion of ice is 334 kJ/kg. May 21, 2010 #4 PaulS1950. This is for a hot tub, I do not need to increase or decrease the temperature. I have done the calculation again manually in an Excel spreadsheet and got the same result. watts) to water. 250 us gallons at 105f with moderate insulation… would 100 watts DC heater maintain this temperature? It complains when volume is 0.25 US gallon, saying volume must be greater than zero. 1 Watt = 1 Joule of energy per second 1 kW = 1000 Joules of energy per second. • The heat content of one gallon of fuel oil roughly equals that of 41 kWh of electricity, 137 cubic feet of natural gas, 1.5 gallons of propane, 17.5 pounds of air-dried wood, 17 pounds of pellets, a gallon of kerosene, or 10 pounds of coal. This unit is less used than it was. heat of vaporization of water is 2256 kJ/kg. This way a circulation develops in the water container given the shape of the water container permits it. It also should be noted that the difference between the starting temperature and the desired final application temperature is commonly referred to as delta T (ΔT). Thanks!!! 1 meter cube = 1000 Ltrs I'm under the impression that a Calorie (kcal) heats one liter of water by one degree, and so heating one liter by 35 degrees requires 35 Calories. There are those who tell us what they want as they know their exact requirements. There is 3.785 liters per US Gallon so these figures are 129.45 MJ of heat energy per US Gallon which is equal to 35.96 kWh of heat energy per US Gallon. It takes about 1/10 kWh of energy to boil a litre of water and around 5kWh to heat a bath. One question which comes up time and again is “How many kW do I need to heat up my tank?”. Great calculator. Power = Energy / time However this will require a much lower watt density than on a oil heater. The immersion stat will control temperature which will normally be well under boiling point - so 65 degrees or so, depending on what it is set at. 1) thermal transfer from heat source to water 2) As the water is heating up, the loss of water temperature due to conduction to the cooler surrounding air. at 1:57 PM. As 1 litre of water needs about 1.16 watts to raise it through 1°C in an hour, a 120 litre tank of cold mains water needs a total energy input of about 7800 watts-hours (120*1.16*56) to raise its temperature to the required level. This calculator tells you how long it takes to heat water from start to end temperature with a given heating power. We normally see energy in our electricity meter and bill as kilo-watt hours, rather than kilo-joules, so we have to divide by 3,600 (the number of seconds in an hour) to convert them — so 18,900 KiloJoules is 5.25 kilowatt-hours (18900 ÷ 3600 = 5.25) So basically I use 5.25 electricity credits every day heating up water. The immersion stat will control temperature which will normally be well under boiling point - so 65 degrees or so, depending on what it is set at. Where C p is the heat capacity of water (1 BTU/lb/F) and m is the mass of the water (Assume 1 gal has 8.3 lb of water and the 3,412 BTU = 1 kWh) Solution: Energy required for heating the water to 120°F: = m × C p × ΔT = 100 gal day × 8.3 lb gal ︸ m × 1 BTU lb °F ︸ C p × (120 − 65) °F ︸ ΔT = 100 gal day × 8.3 lb gal × 1 … Heating oil provides 138,500 British thermal units (BTU) per US gallon; 1 BTU = 0.000293 kWh; 1 US gallon = 3.78541178 litres (138,500 * 0.000293)kWh in 3.78541178 litres (138,500 * 0.000293)/3.78541178 kWh/litre = 10.720233982047786621512547837002 One kWh is 3413 Btu's, so one Btu is 0.000293 kWh. I know that "both heat of vaporization plus the heat required to raise the water to 100°C" but the energy required to raise the water to 100°C contributes just 5% of the total requirement . Hi John, If you have problems with the units, feel free to use our temperature conversion or weight conversion calculators. The calculators on this page compute how long it takes to heat water, how much energy is consumed, and how much heating power is required. Energy E = m•Cp•ΔT = 7000 x 4.186 x 60 = 1758120 kJ So, this is 12.8889 kWh/liter of heat energy.