Problem: Boston, sorry to all the New York people, had to do it.
Given: 100 feet cubed
Approach: So the annual cost of heating is going to depend on how much fuel which depends on how much energy and we know the heating valu...
Calc: The building is heated with natural gas which has an average heating value of a thousand BTU per cubic foot and an average cost...
Calc: The boiler efficiency is 80% what is the annual cost of heating.
Result: Best answer choice is C.
Office Hours
1
Student questions asked in live office hours about this problem
OH 24: HVAC 18
Q: I have three related questions about heating degree days: how to apply them in HVAC-18 and 21, why you can't plug HDD directly into the formula Q = U × A × HDD × 24, and where to find these formulas in the reference handbook.
A: The key insight is that the HDD formula requires the ΔT to match the base temperature used to calculate the degree days — plugging in raw HDD without checking the baseline will give you the wrong result. Search for 'degree days' in the reference handbook to find the relevant equations; they're in the HVAC energy analysis section.