HVAC Lab–Energy Question

Question:

I am confused by the units and figures in the E_airflow portion of question 2.  For the calculation in row 32, "Energy brought in by ventilation airflow, Ev:", the only related equation I could find gives E_airflow = m x [0.24T + W(0.45T + 1061)].  I have already calculated m.  I imagine that T is temperature, but is it temperature difference, indoor temperature, or outdoor temperature?  I see that the answer should have units of btu/h.  So far with m, I have lb/h.  How do I get from lb to btu, and what is this W for?  Also, are the rest of the values in this equation constants, or do they need to be modified for our figures?

Response:

• If you look at the Parameter Definitions above you’ll find the meaings of T, W, Q and other terms used in the lab.  The subscripts define indoor and outdoor conditions.
• You are given the equation in the instructions to calculate the energy.  Note that it’s units are BTU/hr.