Sustainable Energy
2nd Edition
ISBN: 9781337551663
Author: DUNLAP, Richard A.
Publisher: Cengage,
expand_more
expand_more
format_list_bulleted
Concept explainers
Question
Chapter 8, Problem 6P
To determine
Find the heat loss in
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
A typical ceiling of a house consists of items shown in the accompanying table. Assume an inside room temperature of 21° C and an attic air temperature of −10° C, with an exposed area of 100 m2 . Calculate the heatloss through the ceiling.
Calculate the heat loss from a double-pane glass window consisting of two pieces of glass, each having a thickness of 10 mm with a thermal conductivity of k = 1.3 W/m.K . The two glass panes are separated by an air gap of 7 mm. Assume thermal conductivity of air to be k = 0.022 W/m.K .
A typical ceiling of a house consists of items shown in the accompanying table. Assume an inside room temperature of 70F and an attic air temperature of 15F, with an exposed area of 1000 ft2. Calculate the heat loss through the ceiling.
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, civil-engineering and related others by exploring similar questions and additional content below.Similar questions
- For a building located in London, England with annual heating degree-days (dd) of 5634, a heating load (heat loss) of 42,000 kj/h, and a design temperature difference of 35° C (20° C indoor), estimate the annual energy consumption. If the building is heated with a furnace with an efficiency of 98%, how much gas is burned to keep the home at 20° C? State yourassumptions.arrow_forwardWe have exposed 1 kg of water, 1 kg of brick, and 1 kg of concrete each to a heat source that puts out 100 J every second. Assuming that all of the supplied energy goes to each material and they were all initially at the same temperature, which one of these materials will have a greater temperature rise after 10 s? We can answer this question using Equation as shown . We will first look up the values of the specific heat for water, brick, and concrete, which are cwater = 4180 J⁄kg K, cbrick = 960 J⁄kg K and cconcrete = 880 J⁄kg K . Now applying as shown , Ethermal = mc(Tfinal Tinitial) to each situation, it should be clear that although each material has the same amount of mass and is exposed to the same amount of thermal energy, the concrete will experience a higher temperature rise because it has the lowest heat capacity value among the three given materials.arrow_forwardReplacing incandescent lights with energy-efficient fluorescent lights can reduce the lighting energy consumption to one-fourth of what it was before. The energy consumed by the lamps is eventually converted to heat, and thus switching to energy-efficient lighting also reduces the cooling load in summer but increases the heating load in winter. Consider a building that is heated by a natural gas furnace with an efficiency of 80 percent and cooled by an air conditioner with a COP of 3.5. If electricity costs $0.12/kWh and natural gas costs $1.40/therm (1 therm = 105,500 kJ), determine if efficient lighting will increase or decrease the total energy cost of the building (a) in summer and (b) in winter.arrow_forward
- A 75 gal. electric hot water heater provides 9000 Watts of power to heat water. If the heater is filled with water at an initial temperature of 50ºF, how long will it take for the water to reach 140ºF? Assume that there are no heat losses.arrow_forwardFor a building located in Madrid, Spain with annual heating degree-days (dd) of 4654, a heating load (heat loss) of 30,000 kj/h, and a design temperature difference of 30° C (20° C indoor), estimate the annual energy consumption. If the building is heated with a furnace with an efficiency of 92%, how muchgas is burned to keep the home at 20° C? State your assumptions.arrow_forwardA heat pump supplies heat energy to a house at the rate of 140,000 kJ/h when the house is maintained at 25°C. Over a period of one month, the heat pump operates for 100 hours to transfer energy from a heat source outside the house to inside the house. Consider a heat pump receiving heat from two different outside energy sources. In one application the heat pump receives heat from the outside air at 0°C. In a second application the heat pump receives heat from a lake having a water temperature of 10°C. If electricity costs $0.105/kWh, determine the maximum money saved by using the lake water rather than the outside air as the outside energy source.arrow_forward
- The air inside a hot-air balloon is heated to 72.00 °C (Tinitial) and then cools to 52.00 °C (Tfinal). By what percentage does the volume of the balloon change?arrow_forwardThe heat exchanger radiates thermal energy at the rate of 2500 kJ/h for each square meter of its surface area. Determine how many joules (J) are radiated within a 5-hour period.arrow_forward
arrow_back_ios
arrow_forward_ios
Recommended textbooks for you
Engineering Fundamentals: An Introduction to Engi...Civil EngineeringISBN:9781305084766Author:Saeed MoaveniPublisher:Cengage Learning
Engineering Fundamentals: An Introduction to Engi...
Civil Engineering
ISBN:9781305084766
Author:Saeed Moaveni
Publisher:Cengage Learning