Goreham Shower Head Economic Analysis
Line Item
Value
Units
Conversion factors
density of water
specific heat of water
volume
8.33
1
748
lbs/gallon
Btu/lb/degree F
gal/HCF
cold water temperature
mixed water temperature
school days per year
number of shower heads
cost to replace shower head
average flow rate before retrofit
average flow rate after retrofit
length of shower
number of resident students
number of showers per day
cost of natural gas
efficiency of CHP and distribution
cost of water
50
110
240
310
55
2.6
1.5
8
1000
1.5
6.5
0.6
7.30
degrees F
degrees F
days/year
heads
$/head
gpm
gpm
min
students
shower/day/student
$/MMBtu
10.83
1500
$/MMBtu
showers/day
cost of heat
cost of water
20.8
10,396
0.11
0.20
gal/shower
Btu's/shower
$/shower
$/shower
cost of heat
cost of water
12
5,998
0.06
0.12
gal/shower
Btu's/shower
$/shower
$/shower
Assumptions
$/HCF
Calculations
cost of heat at shower
number of showers per day
per shower (before retrofit)
per shower (after retrofit)
saved
heat expense reduction
water expense reduction
total expense reduction
project investment
payback
13,200
6.60
200
3,168,000
353
4,235
1,583
17,153
30,918
48,071
17,050
4.3
gal/day
MMBtu/day (at shower)
$/day
gal/year
HCF/month
HCF/year
MMBtu/year (at shower)
$/year
$/year
$/year
$
months