Final answer:
The T/P relief valve typically opens at approximately 210 degrees Fahrenheit (99 degrees Celsius) with a pressure setting around 150 psi. Calculating the opening temperature involves understanding vapor pressure-temperature relationships and the Clausius-Clapeyron equation.
Step-by-step explanation:
The temperature at which a T/P (Temperature and Pressure) relief valve opens is typically set by the manufacturer according to safety standards. It is designed to open and release water or steam if either the temperature or the pressure becomes too high, exceeding the capability of the system it is protecting. For example, in a hot water heating system, a common temperature setting for the T/P relief valve to open would be approximately 210 degrees Fahrenheit (99 degrees Celsius) with a pressure setting of around 150 psi (pounds per square inch).
As the normal boiling point is the temperature at which the vapor pressure equals atmospheric pressure at sea level, calculating the temperature that corresponds to a given vapor pressure requires utilizing the Clausius-Clapeyron equation. If we have known values such as T₁, P₁, and AHvap, we can determine the new temperature T₂ for a different vapor pressure P₂ accordingly.
The most efficient heat transfer in a system occurs when the temperature difference between the hot and cold reservoirs is maximized, which is often regulated by equipment like T/P relief valves to ensure safety. For heat engines, the efficiency is greater when the temperature of the hot reservoir is high and the temperature of the cold reservoir is low, a principle that may similarly influence the design and operation of T/P relief valves.