Sustainable Energy
2nd Edition
ISBN: 9781337551663
Author: DUNLAP, Richard A.
Publisher: Cengage,
expand_more
expand_more
format_list_bulleted
Concept explainers
Question
error_outline
This textbook solution is under construction.
Students have asked these similar questions
A 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.
calculate the heat loss through the ceiling, if the R-19 insulation batt is replaced by R-40 fiberglass insulation.
A house has a volume of 1200 m3 (a) What is the total massof air inside the house at 15°C? (b) If the temperature dropsto –15°C what mass of air enters or leaves the house?
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
- Replacing 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_forwardFor 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_forwardTake a 4,000 G.S.F. home from 8290 CFH to 1409 CFH in a climate with 4246 HDD. What are the savings? Give your answer in Btus of heating energyarrow_forward
- The 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_forwardAn electrical current flows through a long bar, generating thermal energy at a rate uniform volumetric of q = 2 × 105 W/m 3. The bar is concentric with a hollow ceramic cylinder, creating an air-filled space between the two. If the external surface temperature cannot exceed 40 °C, what is the minimum speed that the ambient air should be blown? the neighborhood meets at 25 °C and the emissivity of the ceramic is 0.8. If the bar has an emissivity of 0.2, what is the bar surface temperature?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