Part 2-5 Appliance energy breakdown / pie charts

For the home we estimated the appliance energy breakdown is below:

Pie chart from energy company:

Part 2-4 Heating and Cooling Energy needs for the home

Qheat = (UA + mdot * Cpa) * HDD
Qcool, sensible = (UA + mdot * Cpa) * CDD
Qcool, latent = mdot * hfg * SUM(wb-wo)deltaT

Cp=0.2441 Btu/lb

mdot=211.8 lb/hr

hfg=970.34 Btu/lb

Qheat = (UA + mdot * Cpa) * HDD

          =[(337.24Btu/F*hr)+(211.8 lb/hr)*(0.2441Btu/lb*F)] * 7228F*day (24hr)
          = 67470199 Btu 


Qcool, sensible = (UA + mdot * Cpa) * CDD
                          = [(146.76Btu/F*hr)+(211.8 lb/hr)*(0.2441Btu/lb*F)]*1270*day(24hr)
                          =6049072 Btu

Qcool, latent = mdot * hfg * SUM(wb-wo)deltaT
                     = (211.8 lb/hr)(970.34 Btu/lb)(22.48 hr) = 4620045 Btu

Part 2-3 Ventilation Rate of the Home

Assuming standard air exchange for homes, the ventilation rate was calculated as follows:

Desired air exchange rate = 0.35
8 ft ceilings

Ventilation rate = Volume*air exchange rate = (1000ft*8ft)(0.35/hr)(1hr/60min) = 46.67 cfm

or Q=mdot/density of air = (3.53 lb/min)/(0.0757lb/ft^3) @ 65 degrees F =  46.63 cfm

Part 2-2 Determine the heating and cooling degree days for a typical year

The heating degree days in Iowa City from 10/1/2010-09/1/2011 are shown below



The cooling degree days in Iowa City from 10/1/2010-09/1/2011 are shown below

Total heating degree days in a year in Iowa City = 7228

Totla cooling degree days in a year in Iowa City = 1270

Part 2-1 of project: R-values and overall thermal conductance of building materials

Part 2 of the project will consider a standard size (1000 sq. ft.), 2-bedroom, one story home with no basement. The group chose Iowa City as the location. (If you don't bleed black & gold...)

1. List the R-values of the building materials and compute the overall thermal conductance (UA) of the home.

When calculating the R-values of the building materials, some assumptions of the types of materials that were used had to be made. These are reflected in the table below

The overall thermal conductance was calculated using the general equation UA= (1/Rvalue)*(Area) for each total R-value and summing up those terms. The total R-values and total areas are shown in the table below.

*The floor of a slab home needs to be considered for sizing a furnace but not an air-conditioner.