Solar Design & Thermal Comfort: Case Study Analysis Essay

Successful completion of this assignment will demonstrate:

• Understanding of the interaction between building fabric/form and solar irradiation, and building thermal performance and how local environmental conditions and the design of a building affect the thermal comfort of its occupants.

• Ability to make practical application of calculation methods for energy flows and lighting in buildings, and hence characterise building performance.

• Understanding of the principles of daylighting and how daylighting design can impact on the thermal performance of buildings.

• Ability to do independent research and make reasonable assumptions based on relevant scientific and/or practice based literature.

• Ability to write a client report giving recommendations for maximising the benefits of sunlight while minimizing overheating risk.

Solar gains are beneficial in winter to offset demand for heating, but can contribute to overheating in the summer. Avoiding overheating due to solar gains is a key design requirement to minimise the use of mechanical cooling and reduce energy consumption by cooling systems. Under Part L1A of the 2013 Building Regulations for England, there is now an explicit requirement to limit heat gains to dwellings.

Good low energy design will seek to minimise the effect of excessive solar gains in summer by appropriate orientation, massing and selection of the building façade. Your role as a consultant is to advise on suitable orientation and construction methods for a case study dwelling to a) benefit from solar gains and natural daylight when appropriate (i.e. in colder months) and b) do not suffer from problems of excessive gains in summer.

You need to provide your recommendations for three different UK locations: Edinburgh, Manchester and London.

Case Study: Floor plan of the case study dwelling (bungalow) along with all the dimensions that you need are given in the appendix. All windows are manually controlled by the occupants. All windows are 6 mm hard coat low emissivity double glazing with internal blinds. None of the doors has any glazing. There is no external shading.

1. Identify potential sources of heat gain during summer and their likelyoperation/occupancy profile in each room. This should include a list of typical equipment that can be found in a home. Discuss different mechanisms of heat transfer for each source.

2. For each room calculate internal casual gains per unit floor area from equipment, people and lighting that you identified in Task 1. You should use method b (detailed method) discussed in section 5.2 of CIBSE TM37 (2006) and state any assumptions that you make and any formula that you use. You should also provide references for the values that you use in your calculations.

3. For each room calculate solar gains (solar load) per unit floor area for a peak summer day* for three different locations: a) Edinburgh b) Manchester c) London. Calculating solar gains are explained in section 5 of CIBSE TM37 (2006) (uploaded on blackboard). For this task you should assume that the front of the house** is facing north.

4. The solar gains in each room will be dependent on the building orientation. Calculate the solar gains per unit floor area for three other orientations (i.e. every 90 degrees)for each location.

5. For each location and orientation calculate the total gains (solar plus internal gains from equipment, people and lighting) and compare the total load with the maximum recommended value in Approved Document L2A***. You then need to select the most suitable orientation that could maximise use of solar gains in winter while avoid overheating in summer.

The combined solar and internal casual gains on peak summer days (corrected fo geographical location) should not be greater than 35 W/��2 of floor area in each occupiedspace.

6. Discuss the suitability of different construction methods (e.g lightweight vs heavyweight) and their influence on solar gains and indoor temperatures during the summer. Support your discussion with the relevant literature.

7. Discuss the suitability of different thermal comfort approaches if a detailed overheating analysis was needed. Support your discussion with the relevant literature.

8. Calculate the average daylight factors for each room and comment on the suitability of level of daylight. You can refer to section 3.4.3 of CIBSE lighting guide 10 (2014) (uploaded on blackboard) for how to calculate average daylight factors.

9. Produce a client report covering Tasks 1 – 9; marks are given for quality of writing, structure, use of references, presentation. The length of your report should be no more than 3000 words, excluding references.