how many btu"s does it taketo raise onepound of water at 32 f to the boiling point at 14.7psia and then to staem.?
To calculate the number of BTUs required to raise one pound of water at 32°F to the boiling point at 14.7 psia and then convert it to steam, we need to consider the following steps:
1. Heat water from 32°F to its boiling point: To determine the heat required for this step, we can use the specific heat capacity of water. The specific heat capacity of water is 1 BTU/(lb°F). Therefore, the heat required can be calculated as:
Q1 = (Temperature final - Temperature initial) x Mass x Specific heat capacity
= (212°F - 32°F) x 1 lb x 1 BTU/(lb°F)
Q1 = 180 BTUs
2. Convert water into steam at boiling point (100°C or 212°F): To calculate the heat required for this phase change, we use the latent heat of vaporization for water, which is the amount of heat energy required to convert water into steam at the boiling point. The latent heat of vaporization for water is approximately 970 BTU/lb.
Q2 = Mass x Latent heat of vaporization
= 1 lb x 970 BTU/lb
Q2 = 970 BTUs
Therefore, the total number of BTUs required to raise one pound of water at 32°F to the boiling point at 14.7 psia and then convert it to steam is:
Total = Q1 + Q2
= 180 BTUs + 970 BTUs
Total = 1150 BTUs