Question

4. Commercial building energy analysis. This problem analyzes how large commercial buildings use using data from the Photonics Center In particular, we want to compare the energy needed to condition the air flowing through the building, with the energy needed to 1) provide heat in the winter to balance the heat loss from the walls to the environment, and 2) provide the necessary cooling in the summer time to overcome the heat gain from the outside air (lets ignore solar gain for now). The expectation is that we use a lot more e relative to the energy actually lost or gained through the walls. energy for HVAC to condition the large air flows, In HVAC as push the air through the building. The minimum amount of air flow is typically determined by the HVAC designer to meet the ventilation requirements, and additional air is used to meet the buildings heating and cooling requirements determined by local thermostats. systems, energy is used to heat &cool the air, as well Below are the numbers that describe the operation of the photonics building. You are to compare the energy condition the air in a winter and a summer month, based on the average outdoor air temperature for that month, with the energy loss or gain for those months through the walls of the building Note, for summer, assume that the air comes in and is cooled to 55 F, and then heated up to 65F. Do include the energy used to push the air through the building, and develop a table that indicates the different uses for energy needed to Typical air flow: 334,000 cfm Building R value: 10 R (ft 2 F hr /btu) Building exposed area: 175,000 ft*2 chiller: .5 kw/ton of cooling Avg HP for supply/return fans: 450 HP boiler efficiency: 85% Summer temp: 80F Winter temp: 35 F Indoor temp: 70 F I recommend that you develop a spreadsheet, but first draw a sketch of the energy flows your trying to capture, and group the related equations together.

Answer 1