16469- Low Energy Building Design Presentation 3- Demand/Supply Matching

1. Marc Smeed Edmund Tsang Graham Dow 16469- Low Energy Building DesignPresentation 3- Demand/Supply Matching

2. DEMAND REDUCTION STARTCIBSE ‘TYPICAL PRACTICE PRIMARY SCHOOL’

3. AIR TIGHT CONSTRUCTION • Assumptions • Heating Period External Temp = 8.6°C1 • Design Internal Temp = 21°C Calculated Heat Loss, per m2 per hour = 4.04W/m2h Calculated Heat Loss, per m2 per hour = 1.61W/m2h Saving = (4.04-1.61)/4.04 * 100% =60% Energy Saving = 27.2 kWh/m2 p.a. 1. ESP-r data output: (Average external temp for heating season)

4. DEMAND REDUCTION CIBSE ‘TYPICAL PRACTICE PRIMARY SCHOOL’

5. HEAT RECOVERY • Assumptions • External Temp = 8.6°C1 • Design Internal Temp = 21°C • Exchanger εs = 65%2 • Occupied days per year = 1903 • Occupied hours per day = 8 • Ceiling Height = 3m • Total Building Ventilation Rate = 1.5 ACH qs = εs*mmin*Cp*(∆T) = 65%*(0.00125*1.284)*1.014*11 = 0.0116kW/m2 Heat flow rate through sensible heat exchanger4 Occupied hours in the year = 1520 Heat Recovered = 17.7 kWh/m2 p.a. 1. ESP-r data output: (Average external temp for occupied hours) 2. CIBSE Guide F: Table 4.6,p.4-13 3. www.cumbria.gov.uk 4. ASHRAE Handbook 2004: Chapter 44

6. DEMAND REDUCTION CIBSE ‘TYPICAL PRACTICE PRIMARY SCHOOL’

7. DEMAND REDUCTION CIBSE ‘TYPICAL PRACTICE PRIMARY SCHOOL’

8. FOSSIL FUELS 79% LIGHTING CONTROL • Assumptions ELECTRICITY 21% 1.

9. LIGHTING CONTROL • Assumptions LIGHTING = 10/21 % OF ELECTRICAL LOAD = 47% = 15.2kWh/m2p.a. 1.

10. LIGHTING CONTROL Occupancy sensors can reduce lighting load by 30-40%1 This can rise to 75% if integrate with PSALI1 Therefore we can assume that we could obtain at least 35% reduction. 35% X 15.2kWh/m2 = 5.33kWh/m2 Energy Saving= 5.33 kWh/m2 p.a. 1. www.advancebuildings.org

11. DEMAND REDUCTION CIBSE ‘TYPICAL PRACTICE PRIMARY SCHOOL’

12. ENERGY STORAGE

13. FLYWHEEL • A rotor is accelerated, maintaining the energy in the system as inertial energy • Maximum Power rating of 2000KW for a multi-cabinet type • Maximum Power rating of 500KW for a single-cabinet type • Stored energy discharges at a maximum time of 2 minutes

15. FLYWHEEL- FEASIBILTY • ADVANTAGES • Flexible • Commercially available • High power outputs • DISADVANTAGES • Safety concerns • Short discharge times • Expensive

16. HYDROGEN STORAGE • The 3 key elements are • Electrolysis Mechanism • Hydrogen Storage • Fuel Cell • Hydrogen stored via • Pressurised storage • Ammonia • Metal hydrides

17. FEASIBILITY • High storage capacity- around 165 KWh /m3 • Only pressurised hydrogen storage is currently available for building use • Other storage only commercially available for vehicles • Expensive

18. THERMAL ENERGY STORAGE TWO TYPES • Sensible • A Tank underground, used for heat storage (25kWh/m^3) • Latent • Higher energy density (around 100kWh/m^3) • Phase change materials (PCM) used where it solidifies during night then melts during the day

19. Demand Shifting

20. Purpose of Demand Shifting • Demand shifting makes use of storage so that peaks and troughs of demand are levelled off • Requires intelligent forward thinking • Can be remotely managed system and use predictions to help shift loads

21. What's to be gained • Throttling a CHP system is not required • Constant power generation can be attained, decrease maintenance problems • Can help incorporate renewable systems

22. DEMAND SHIFTING FOR RENEWABLES • Demand shifting can be used to create demand when it suits a renewable supply. • For Example- Solar works when there are higher levels of solar intensity- i.e. in the summer/midday.

24. SHOULD WE DECOUPLE?

25. VISION What is going to be different about our School? • A ‘HYDROGEN’ school • A DECOUPLED school A NEW approach to school design

26. Any Questions ?