Design the power of the electric heating tube of the water tank, without considering the heat loss, can be calculated by the following formula;
The calculation formula is: required power (kw) = weight of water (kg) * temperature difference * specific heat capacity of water {kJ/(kg·℃)}/time (seconds)
Then know the formula, it is actually very easy to calculate the power of the heating tube, we only need to know the weight of the water, the time required for heating, the value of the temperature difference and the specific heat capacity of the water.
Among them, the parameter that is somewhat confusing to everyone should be the specific heat capacity of water {kJ/(kg·℃).
The Baidu entry for the specific heat capacity is
Specific Heat Capacity (symbol c), abbreviated as specific heat, also known as specific heat capacity, is a physical quantity commonly used in thermodynamics, representing the ability of an object to absorb heat or dissipate heat. The greater the specific heat capacity, the stronger the object's ability to absorb or dissipate heat. It refers to the amount of heat absorbed or released per unit mass of a substance that increases or decreases per unit temperature. The unit in the International System of Units is Joule per kilogram Kelvin [J/( kg · K )], that is, the energy required to increase the temperature of 1 kg of matter by 1 Kelvin.
Wikipedia's explanation of specific heat capacity is
Heat capacity or thermal capacity is a measurable physical quantity equal to the ratio of the heat added to (or removed from) an object to theresulting temperature change.[1] The unit of heat capacity is joule per kelvin, or kilogram metre squared per kelvin second squared in the International System of Units (SI). The dimensional form is L2MT−2Θ−1. Specific heat is the amount of heat needed to raise the temperature of one kilogram of mass by 1 kelvin.
So, for example, the specific heat capacity of water is actually the heat (joules) required for 1g of water to heat up by 1 degree Celsius, and the specific heat of water is 4.17J/(g·℃).
That is to say, 4.17J of heat is required to increase the temperature of 1g of water by 1°C.
Expand the specific heat of ice
The specific reference is as follows
It takes 2.03J of heat to increase the temperature of 1g of ice by 1°C.
Specific heat capacity of common substances
Specific heat of water: 4.179J/(g·℃)
Specific heat of air: 1.01J/(g·℃)
Specific heat of wood: 1.76J/(g·℃)
Specific heat of aluminum: 902J/(g·℃)
Specific heat of gold: 129J/(g·℃)
Specific heat of iron: 450J/(g·℃)
Power Design of Electric Heating Tube for Water Tank
for example:
For example, if the initial temperature is 10°C, what is the power of the electric heating tube required to heat 500kg of water to 90°C in 60mins (3600s)?
Required power (kw) = weight of water (kg) * temperature difference * specific heat capacity of water {kJ/(kg·℃)}/time (sec)
Substitute the formula to calculate the total power=500*(90-10)*4.17/3600=46.33kw
The above is the calculation method for the power of the electric heating tube of the water tank.