Simplest Experimental Method to Determine Heat Gain from an Engine in a Room

[Paul9]

Homework Statement

This isn't an assignment per se but rather a thought exercise proposed by a professor during class. The scenario is that you have a room where an internal combustion engine is used to run a machine. You have no information about the machines power output or efficiency. The only thing you know is that the engine exhaust is vented straight to the outside of the building, and the engine intake is also taken straight from the outside of the building. (e.g. the intake/exhaust is isolated from the room)

The question: What would be the simplest experimental method to determine the steady state heat gain in the room when the engine is running.2. The attempt at a solution

My first thought was to use an array of thermometers to measure the average temperature in the room at steady state with the engine off and then with the engine on. Then heat should simply be:

Q = density of air * Volume of Room * C_p(T_on-T_off)

Seems straightforward enough but then the question arises of how many thermometers are needed and how one should place them in order to determine the average room temperature.

Can anyone think of a simpler method?

 

[KataKoniK]

I would suggest using a heat flux sensor or a heat flow meter to directly measure the heat gain in the room. These instruments can be placed at different locations in the room, including near the exhaust and intake vents, to get a better understanding of the heat transfer in the room. Additionally, using a thermal imaging camera can also provide visual evidence of the heat gain in the room.

Another method would be to use a power meter to measure the energy consumption of the engine and calculate the heat gain based on the efficiency of the engine. This method would require knowing the power output of the engine, but it could provide a more accurate measurement of the heat gain in the room.

In terms of the number and placement of thermometers, it would depend on the size and layout of the room. Ideally, the thermometers should be placed evenly throughout the room to get a representative average temperature. Alternatively, using a data logger with multiple temperature sensors can provide continuous data and eliminate the need for manual readings.

Overall, the most important aspect of any experimental method is to ensure that the measurements are accurate and reliable. It may be beneficial to combine multiple methods to get a more comprehensive understanding of the heat gain in the room.