In this problem you will estimate the heat lost by a typical house, assuming that the temperature inside is T(in) = 20 degrees celcius and the temperature outside is T(out) = 0 degrees celcius
. We will take the thickness of the walls and ceiling to be L(wall) = 12 cm. Assume that the house is a cube of length L = 9.0 m on a side. Assume that the roof has very high conductivity, so that the air in the attic is at the same temperature as the outside air. Ignore heat loss through the ground.
a)What is H, the total rate of energy loss due to heat conduction for this house?
b)Let us assume that the winter consists of 150 days in which the outside temperature is 0*C on average. This will give the typical number of "heating degree days" observed in a winter in Vancouver. Given that heating oil has an energy content of 35 MJ per litre when burned, how much oil will be needed to supply the heat lost by conduction from this house over a winter? Assume that the heating system is 75% efficient.
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In this problem you will estimate the heat lost by a typical house, assuming that the temperature inside is T(in) = 20 degrees celcius and the temperature outside is T(out) = 0 degrees celcius
In this problem, you will estimate the heat lost by a typical house, assuming that the...
In this problem, you will estimate the heat lost by a typical house, assuming that the temperature inside is Tin=20∘C and the temperature outside is Tout=0∘C. The walls and uppermost ceiling of a typical house are supported by 2×6 inch wooden beams (kwood=0.12W/(mK)) with fiberglass insulation (kins=0.04W/(mK)) in between. The thickness of the wall is Lwall=18cm allowing for interior and exterior covering. Assume that the house is a cube of length L=9.0m on a side. Approximate that the roof has...
Heat Loss and Heating Costs of a House Part A A house has well-insulated walls 17.1...
Heat Loss and Heating Costs of a House Part A A house has well-insulated walls 17.1 cm thick (assume conductivity of air) and area 411 m2, a roof of wood б.бб cm thick and area 279 m2, and uncovered windows 0.626 cm thick and total area 33.4 m2. Assuming that the heat loss is only by conduction, calculate the rate at which heat must be supplied to this house to maintain its temperature at 21.4°C if the outside temperature is...
Outside it is 11∘C (52∘F), and inside your house you maintain 23∘C (73∘F). By how many...
Outside it is 11∘C (52∘F), and inside your house you maintain 23∘C (73∘F). By how many percent could you reduce your heating bill if you reduced the inside temperature by 4∘C to 19∘C (66∘F)? Consider only heat loss by conduction through the walls and roof, and assume that your bill is proportional to your energy consumption.
(10 point) 60. A typical exterior masonry wall of a house, shown in the accompanying figure,...
(10 point) 60. A typical exterior masonry wall of a house, shown in the accompanying figure, consists of the items in the accompanying table. Assume an inside room temperature of 68F and an outside air temperature of 10F, with an exposed area of 150 ft2. Calculate the heat loss through the wall. Items Resistance 1. Outside film resistance (winter. 15 mph wind) 2. Face brick (4 in. 3. Cement mortar (1/2 in.) 4. Cinder block (8 in) 5. Air space...
On a cold day, 26100 J of heat leaks out of a house. The inside temperature is 22 °C, and the outside temperature is -20...
On a cold day, 26100 J of heat leaks out of a house. The inside temperature is 22 °C, and the outside temperature is -20 °C. What is the increase in the entropy of the universe that this heat loss produces?
Heat Transfer Problems 1. A window pane (1/8 inch thick) in an old house owned by...
Heat Transfer
Problems 1. A window pane (1/8 inch thick) in an old house owned by a professor is 3 ft. by 4 ft. He likes to be warm in the winter so the inside temperature is kept at 70 °F even when the outside temperature is 10 •F. For this problem assume the inside and outside temperatures are for the window surface. How much heat is transferred through the window (k=.54 BTU/hr ft ° F)? 2. A small heated...
Consider a house that has a 10-m x 20-m base and a 4-m-high wall. All four...
Consider a house that has a 10-m x 20-m base and a 4-m-high wall. All four walls of the house have an R-value of 2.31m2°C/W. The two 10-m x 4-m walls have no windows. The third wall has five windows made of 0.5-cm-thick glass (k = 0.78 W/m-K), 1.2m x 1.8min size. The fourth wall has the same size and number of windows, but they are double paned with a 1.5-cm-thick stagnant air space (k = 0.026 W/m-K) enclosed between...
Homework 7 heat transfer 2018-20 1) A horizontal tube of 12.5-mm dimeter with an outer srface temperature of 240°C is placed in a room with an air temperature of 20°C. Estimate the heat transfer rate...
Homework 7 heat transfer 2018-20 1) A horizontal tube of 12.5-mm dimeter with an outer srface temperature of 240°C is placed in a room with an air temperature of 20°C. Estimate the heat transfer rate per unit length of the tube due to free convection. 2) Air at -10°C flows at 10 m/s over the roof plate of two 5m length rooms whose air is at Too-200C. The roof plate is 0.20-m thick concrete (k = 0.6 w/ m. K)....
4. Commercial building energy analysis. This problem analyzes how large commercial buildings use using data from...
4. Commercial building energy analysis. This problem analyzes how large commercial buildings use using data from the Photonics Center In particular, we want to compare the energy needed to condition the air flowing through the building, with the energy needed to 1) provide heat in the winter to balance the heat loss from the walls to the environment, and 2) provide the necessary cooling in the summer time to overcome the heat gain from the outside air (lets ignore solar...
summarizr the followung info and write them in your own words and break them into different...
summarizr the followung info and write them in your own words and break them into different key points. 6.5 Metering Chamber: 6.5.1 The minimum size of the metering box is governed by the metering area required to obtain a representative test area for the specimen (see 7.2) and for maintenance of reasonable test accuracy. For example, for specimens incorporating air spaces or stud spaces, the metering area shall span an integral number of spaces (see 5.5). The depth of...
Heat Loss and Heating Costs of a House Part A A house has well-insulated walls 17.1 cm thick (assume conductivity of air) and area 411 m2, a roof of wood б.бб cm thick and area 279 m2, and uncovered windows 0.626 cm thick and total area 33.4 m2. Assuming that the heat loss is only by conduction, calculate the rate at which heat must be supplied to this house to maintain its temperature at 21.4°C if the outside temperature is...
(10 point) 60. A typical exterior masonry wall of a house, shown in the accompanying figure, consists of the items in the accompanying table. Assume an inside room temperature of 68F and an outside air temperature of 10F, with an exposed area of 150 ft2. Calculate the heat loss through the wall. Items Resistance 1. Outside film resistance (winter. 15 mph wind) 2. Face brick (4 in. 3. Cement mortar (1/2 in.) 4. Cinder block (8 in) 5. Air space...
Heat Transfer
Problems 1. A window pane (1/8 inch thick) in an old house owned by a professor is 3 ft. by 4 ft. He likes to be warm in the winter so the inside temperature is kept at 70 °F even when the outside temperature is 10 •F. For this problem assume the inside and outside temperatures are for the window surface. How much heat is transferred through the window (k=.54 BTU/hr ft ° F)? 2. A small heated...
Consider a house that has a 10-m x 20-m base and a 4-m-high wall. All four walls of the house have an R-value of 2.31m2°C/W. The two 10-m x 4-m walls have no windows. The third wall has five windows made of 0.5-cm-thick glass (k = 0.78 W/m-K), 1.2m x 1.8min size. The fourth wall has the same size and number of windows, but they are double paned with a 1.5-cm-thick stagnant air space (k = 0.026 W/m-K) enclosed between...
Homework 7 heat transfer 2018-20 1) A horizontal tube of 12.5-mm dimeter with an outer srface temperature of 240°C is placed in a room with an air temperature of 20°C. Estimate the heat transfer rate per unit length of the tube due to free convection. 2) Air at -10°C flows at 10 m/s over the roof plate of two 5m length rooms whose air is at Too-200C. The roof plate is 0.20-m thick concrete (k = 0.6 w/ m. K)....
4. Commercial building energy analysis. This problem analyzes how large commercial buildings use using data from the Photonics Center In particular, we want to compare the energy needed to condition the air flowing through the building, with the energy needed to 1) provide heat in the winter to balance the heat loss from the walls to the environment, and 2) provide the necessary cooling in the summer time to overcome the heat gain from the outside air (lets ignore solar...
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