Learning Outcomes:
1) Evaluate the effects of human comfort levels on the design of built environments.
2) Examine and appreciate the codes and regulations relating to heat, light, sound and their air flow.
3) Determine the appropriate levels for given circumstances and perform associated calculations relating to heat, light, sound and their air flow.
4) Use scientific experimental methodology to give valid conclusion from observed behaviour relating to environmental sciences.
Portfolio Questions
Q1 Thermal calculations: As issued in taught session
In the above housing project, the cavity walls are constructed as follows.
Brickwork outer leaf 103mm, air-gap 50mm, expanded insulation board 40mm, lightweight concrete block inner leaf 115mm, lightweight plasterboard 10mm
The relevant values of thermal conductivity in W/mK are:
Brickwork: 0.84, Polystyrene 0.025, Concrete block 0.18, Plasterboard 0.18
The standard thermal resistances in m2K/W are:
Outside Surface resistance: 0.06, Inside Surface resistance: 0.12, Air gap: 0.18
(a) Calculate the U-value of this wall. (Show all your calculations)
(b) In order to achieve higher energy performance standards, If you need to achieve a target U- value of 0.28, what thickness of insulating material would you have to use? (Show all your calculations).
Q2 Natural Light, properties of Light calculations & Artificial lighting (Lumens Method): (as issued in the taught session)
(a) Calculate the luminance of the CIE standard sky at 300 if the luminance at the zenith is taken to be 2200cd/m2.
(b) The natural illuminance at a point inside a room is 430 lux and the illuminance given by an unobstructed sky is assumed to be 5380 lx. Calculate the daylight factor at that point.
(c) For an office room, use the formula for the average daylight factors to calculate an average daylight factor for this room and compare it with the description in the text. How would you improve the daylight factor if R=0.5?
(d) A small lamp emits a total luminous flux of 1257 lm in all directions. Calculate the luminous intensity of this light source.
(e) A point source of light has the intensity of 410 cd and radiates uniformly in all directions.
(i) Calculate the quantity of flux into a hemisphere.
(ii) Calculate the average illuminance produced on the inside surface of a hemisphere it has a radius of 1.5m.
(f) A small lamp has a mean luminous intensity of 80 cd. Calculate the maximum direct illuminance the lamp produces on the surface under the following conditions.
(i) At 0.8m from the lamp.
(ii) At a distance of 3.2 m from the lamp.
(g) A street lamp has a uniform intensity of 1200 cd. It is positioned 7m above the centre line of a road which is 8m wide.
(i) Calculate the illuminance on the road surface directly below the lamp.
(ii) Calculate the illuminance at the edge of the roadway.
(h) A workshop is 12m by 6m by 4m high and has work benches 1 m high. Discharge lamps, each with an output of 3700 lm, are fitted in aluminum industrial reflectors at ceiling level. The surfaces have a reflectance of 0.7 for the ceiling and 0.5 for walls. The light loss factor is 0.7. The illuminance required on the workbenches is 400lux.
(i) Find the utilisation factor for the room.
(ii) Calculate the number of lamps required.
(iii) Suggest a reflected ceiling plan layout for them.
Q3 Conduct a survey in the UWL building (Chose one level: Ground level to Level 2).
1) Measure the dimensions of the rooms.
2) Calculate the energy consumption of UWL building
3) Estimate the energy consumption of other spaces, i.e. WC, Corridors, etc.
4) Summarize your results as the overall energy consumption for UWL building per year.
5) Think of the available energy consuming systems and appliances, assess the potential for energy savings and indicate key areas for improvement.
6) Propose improvement methods and technique to increase the building's energy efficiency.