walls are identical. The internal temperature of the building is approximately 18°C and outside temperature is approximately -2°C.The wall has the following specifications: A 30m² area of wall forms one side of a simple 4 walled building where all four
Internal surface resistance 0.120m²K/W
External surface resistance 0.060m²K/W
Cavity resistance 0.180m²K/W
15mm plaster I-value 0.450W/mK 100mm block l-value 0.216W/mK
30mm partial cavity fill l-value 0.036W/mK
102mm brick l-value 0.840W/mK
a. Calculate the U-value and thus the rate of fabric heat loss across the wall.
b. The room is 2.25m high and has two air changes per hour. The volumetric heat capacity of the air is 1300J/m³K.Calculate the rate of ventilation heat loss and thus the total heat loss from the room. You may ignore the loss through the floor and roof. c. What surface area of radiators would be needed to compensate for the above conditions if the radiators output is 400W/m²
d. If the total heat gain received by this room amounts to 10800MJ per heating quarter, calculate the quarterly heating bill, based upon maintaining the thermal comfort within the room if replacement heat costs 2.5p/MJ.