We are determined to provide the latest solutions related to all subjects FREE of charge!

Please sign up to our reward program to support us in return and take advantage of the incredible listed offers.

Enjoy Limited offers, deals & Discounts by signing up to Holooly Rewards Program


Advertise your business, and reach millions of students around the world.


All the data tables that you may search for.


For Arabic Users, find a teacher/tutor in your City or country in the Middle East.


Find the Source, Textbook, Solution Manual that you are looking for in 1 click.


Need Help? We got you covered.

Chapter 9

Q. 9.2

An existing chiller with a capacity of 800 kW and with an average seasonal COP of 3.5 is to be replaced by a new chiller with the same capacity but with an average seasonal COP of 4.5. Determine the simple payback period of the chiller replacement if the cost of electricity is $0.07/kWh and the cost differential of the new chiller is $15,000. Assume that the number of equivalent full-load hours for the chiller is 1,000 per year both before and after the replacement.


Verified Solution

In this example, the energy use savings can be calculated using Eq. (9.12) with SEER_{e} = 3.5, SEER_{r} = 4.5, N_{h,C} = 1,000, Q_{C} = 800 kW,  and  LF_{C} = 1.0 (it is assumed that the chiller is sized correctly):

ΔE_{c}=\dot{Q}_{C}.N_{h,C}.LF_{C}.(\frac {1}{SEER_{e}}-\frac{1}{SEER_{r}})                 (9.12)

ΔE_{c}=800kW*1,000 hrs/yr*1.0*(\frac {1}{3.5}-\frac{1}{4.5})=50,800k Wh/yr

Therefore, the simple payback period for investing in a high-efficiency chiller rather than a standard chiller can be estimated as follows:

SPB=\frac {\$15,000}{50,800k Wh/yr*\$0.07/kWh}=4.2  years

A life-cycle cost analysis may be required to determine if the investment in a high energyefficient chiller is really warranted.