FUND OF ENG THERMODYN-WILEYPLUS NEXT GEN
9th Edition
ISBN: 9781119840589
Author: MORAN
Publisher: WILEY
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Chapter 2, Problem 2.68P
To determine
The rate at which energy is removed by heat transfer from the refrigerated space, and the cost of operating the refrigerator for an entire month.
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A heat pump with a coefficient of performance of 3.5 provides energy at an average rate of
70000 kJ/h to maintain a building at 20 °C on a day when the outside temperature is -5 °C. If the
electricity costs 8.5 cents per kWh. Assume heating is 24 hours a day.
(1) Determine the actual operating cost in $/day.
(2) Determine the minimum theoretical operating cost in $/day.
A heat pump with a coefficient of performance of 3.5 provides energy at an average rate of 70,000 kJ/h to maintain a building at 20 deg C on a day when the outside temperature is -5 deg C. If electricity costs 8.5 cents per kWh,
(a) determine the actual operating cost and the minimum theoretical operating cost, each in $/day.
(b) compare the results of part (a) with the cost of electrical-resistance heating.
By supplying energy to a house at a rate of 25,000 kJ/hr, a heat pump maintains the
temperature of the dwelling at 20 C when the outside air is at -10 C. If electricity
costs 8 cents per kW-hr, determine the minimum theoretical operating cost to heat
the house for 24 hours.
$1.97
O $1.37
$1.75
O $1.51
O$1.64
Chapter 2 Solutions
FUND OF ENG THERMODYN-WILEYPLUS NEXT GEN
Ch. 2 - Prob. 2.1ECh. 2 - Prob. 2.2ECh. 2 - Prob. 2.3ECh. 2 - Prob. 2.4ECh. 2 - Prob. 2.5ECh. 2 - Prob. 2.6ECh. 2 - Prob. 2.7ECh. 2 - Prob. 2.8ECh. 2 - Prob. 2.9ECh. 2 - Prob. 2.10E
Ch. 2 - Prob. 2.11ECh. 2 - Prob. 2.12ECh. 2 - Prob. 2.13ECh. 2 - Prob. 2.14ECh. 2 - Prob. 2.15ECh. 2 - Prob. 2.16ECh. 2 - Prob. 2.17ECh. 2 - Prob. 2.1CUCh. 2 - Prob. 2.2CUCh. 2 - Prob. 2.3CUCh. 2 - Prob. 2.4CUCh. 2 - Prob. 2.5CUCh. 2 - Prob. 2.6CUCh. 2 - Prob. 2.7CUCh. 2 - Prob. 2.8CUCh. 2 - Prob. 2.9CUCh. 2 - Prob. 2.10CUCh. 2 - Prob. 2.11CUCh. 2 - Prob. 2.12CUCh. 2 - Prob. 2.13CUCh. 2 - Prob. 2.14CUCh. 2 - Prob. 2.15CUCh. 2 - Prob. 2.16CUCh. 2 - Prob. 2.17CUCh. 2 - Prob. 2.18CUCh. 2 - Prob. 2.19CUCh. 2 - Prob. 2.20CUCh. 2 - Prob. 2.21CUCh. 2 - Prob. 2.22CUCh. 2 - Prob. 2.23CUCh. 2 - Prob. 2.24CUCh. 2 - Prob. 2.25CUCh. 2 - Prob. 2.26CUCh. 2 - Prob. 2.27CUCh. 2 - Prob. 2.28CUCh. 2 - Prob. 2.29CUCh. 2 - Prob. 2.30CUCh. 2 - Prob. 2.31CUCh. 2 - Prob. 2.32CUCh. 2 - Prob. 2.33CUCh. 2 - Prob. 2.34CUCh. 2 - Prob. 2.35CUCh. 2 - Prob. 2.36CUCh. 2 - Prob. 2.37CUCh. 2 - Prob. 2.38CUCh. 2 - Prob. 2.39CUCh. 2 - Prob. 2.40CUCh. 2 - Prob. 2.41CUCh. 2 - Prob. 2.42CUCh. 2 - Prob. 2.43CUCh. 2 - Prob. 2.44CUCh. 2 - Prob. 2.45CUCh. 2 - Prob. 2.46CUCh. 2 - Prob. 2.47CUCh. 2 - Prob. 2.48CUCh. 2 - Prob. 2.49CUCh. 2 - Prob. 2.50CUCh. 2 - Prob. 2.51CUCh. 2 - Prob. 2.52CUCh. 2 - Prob. 2.53CUCh. 2 - Prob. 2.54CUCh. 2 - Prob. 2.1PCh. 2 - Prob. 2.2PCh. 2 - Prob. 2.3PCh. 2 - Prob. 2.4PCh. 2 - Prob. 2.5PCh. 2 - Prob. 2.6PCh. 2 - Prob. 2.7PCh. 2 - Prob. 2.8PCh. 2 - Prob. 2.9PCh. 2 - Prob. 2.10PCh. 2 - Prob. 2.11PCh. 2 - Prob. 2.12PCh. 2 - Prob. 2.13PCh. 2 - Prob. 2.14PCh. 2 - Prob. 2.15PCh. 2 - Prob. 2.16PCh. 2 - Prob. 2.17PCh. 2 - Prob. 2.18PCh. 2 - Prob. 2.19PCh. 2 - Prob. 2.20PCh. 2 - Prob. 2.21PCh. 2 - Prob. 2.22PCh. 2 - Prob. 2.23PCh. 2 - Prob. 2.24PCh. 2 - Prob. 2.25PCh. 2 - Prob. 2.26PCh. 2 - Prob. 2.27PCh. 2 - Prob. 2.28PCh. 2 - Prob. 2.29PCh. 2 - Prob. 2.30PCh. 2 - Prob. 2.31PCh. 2 - Prob. 2.32PCh. 2 - Prob. 2.33PCh. 2 - Prob. 2.34PCh. 2 - Prob. 2.35PCh. 2 - Prob. 2.36PCh. 2 - Prob. 2.37PCh. 2 - Prob. 2.38PCh. 2 - Prob. 2.39PCh. 2 - Prob. 2.40PCh. 2 - Prob. 2.41PCh. 2 - Prob. 2.42PCh. 2 - Prob. 2.43PCh. 2 - Prob. 2.44PCh. 2 - Prob. 2.45PCh. 2 - Prob. 2.46PCh. 2 - Prob. 2.47PCh. 2 - Prob. 2.48PCh. 2 - Prob. 2.49PCh. 2 - Prob. 2.50PCh. 2 - Prob. 2.51PCh. 2 - Prob. 2.52PCh. 2 - Prob. 2.53PCh. 2 - Prob. 2.54PCh. 2 - Prob. 2.55PCh. 2 - Prob. 2.56PCh. 2 - Prob. 2.57PCh. 2 - Prob. 2.58PCh. 2 - Prob. 2.59PCh. 2 - Prob. 2.60PCh. 2 - Prob. 2.62PCh. 2 - Prob. 2.63PCh. 2 - Prob. 2.64PCh. 2 - Prob. 2.65PCh. 2 - Prob. 2.66PCh. 2 - Prob. 2.67PCh. 2 - Prob. 2.68PCh. 2 - Prob. 2.69PCh. 2 - Prob. 2.70PCh. 2 - Prob. 2.71P
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- A heat pump cycle delivers energy by heat transfer to a dwelling at a rate of 40,000 Btu/h. The coefficient of performance of the cycle is 2.8. Evaluating electricity at $0.085 per kW•h, determine the cost of electricity during the heating season when the heat pump operates for 2000 hours.arrow_forwardIn your own words, define efficiency as it applies to a device designed to perform an energy transformation.arrow_forwardIf a house needs a minimum heat transfer rate of 75 kJ/h (i.e., 75 kJ of heat needs to be transferred into the house during one hour) to maintain a pleasant indoor temperature. If one wants to use a heat pump with a COP of 5.55 to fulfill this heat transfer rate, what is the corresponding electricity (in kWh) consumption to run such a heat pump for one hour?arrow_forward
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