RETROFIT OF DWELLINGS IN CHINESE CITIES

Transcription

1 RETROFIT OF DWELLINGS IN CHINESE CITIES Second year PhD student Loughborough University Christopher Tsang

2 Background Second year PhD student (start in Jan 2016) It forms part of the LoHCool (Low Carbon Climate- Responsive Heating and Cooling of Cities) project, run from the University of Cambridge Supervisors: Prof. Kevin Lomas, Dr. Efi Spentzou, Dr. Candy He

3 The problem Five climate zones in China Hot summer and cold winter zone Room air conditioners are common Fan heaters and electric blanket for heating Indoor temperature versus outdoor temperature in north and south China Increase comfort may lead to tremendous increase in energy use

4 Scale of the research Chongqing 33 million km² City area ~7 million 5473 km² Core area ~0.64 million km² ~200 buildings Source:

5 Research questions 1. How much energy is used by different household in HSCW zone for heating and cooling, and how much energy can be saved by applying retrofit measures in a case study flat? 2. Does retrofit saves the same amount of energy when applied to different urban dwellings? 3. Realistically how much energy can be saved after retrofit?

6 Aim and objectives Aim: To investigate retrofit measures for urban dwellings in the Hot Summer and Cold Winter (HSCW) climate zone in China, in order to efficiently provide occupant thermal comfort and deliver energy savings. The research aim will be achieved through the following objectives: 1. Perform a thorough literature review and identify representative urban dwellings in the context of HSCW zone; 2. Predict the sensitivity of energy demand to alternative building fabrics and occupant behaviour parameters for a case study flat; 3. Calibrate a dynamic thermal model of a case study flat using measured data to predict energy performance and thermal comfort conditions; 4. Apply retrofit measures for a multi-storey building to predict the likely energy savings and variation of thermal comfort conditions; 5. Develop a domestic urban scale model of urban dwellings in HSCW zone to predict the likely energy savings when retrofit measures are applied.

7 Case study building Case study building City centre Bedroom Living room Kitchen

8 Retrofit measures Source: / /1240/10/scale towidth Source: Source: Source: Source:

9 Methodology 1. Looking at a case study flat Compare simulated indoor air temperature with measured data Quantify the potential error in the dynamic thermal model Evaluate the energy savings when retrofit measures are applied for three different kind of energy user (high, medium and low)

10 Methodology 2. Looking at city scale Different performance for different flats in an urban dwelling Different performance for different type of urban dwelling 17% reduction 17% reduction 20% reduction Case study flat: 15% reduction Base case: 15% reduction 12% reduction 10% reduction

11 Methodology 2. Looking at city scale Validate the prediction of energy consumption of typical residential neighbourhoods with literature studies Apply retrofit measures to the archetypal model and draw conclusion on the effectiveness of retrofit Source: Source:

12 Status of the project Completed Calibration of dynamic thermal model (will be briefly discussed in this presentation) In progress Energy savings when apply retrofit measures for different energy users To be completed in year 3 Develop and validate archetypal model Evaluate the effectiveness of retrofit

13 Weather data

14 Model validation

15 Selection of building fabric parameters Building fabric parameter Unit Base case Maximum Minimum Air infiltration ach g-value of glazing U-value of glazing W/m 2 K U-value of external wall W/m 2 K

16 Results for step-by-step calibration Variation of indoor temperature when U-value of wall is changed Variation of indoor temperature when U-value of glazing is changed Variation of indoor temperature when g-value of glazing is changed Variation of indoor temperature when air infiltration is changed

17 Results for step-by-step calibration Combinations of air infiltration rate MBE (%) CvRMSE (%) Starting ΔT ( C) ach= % 2.60% 0.23 ach= % 2.52% 0.21 ach= % 2.49% 0.20 ach= % 2.49% 0.19 ach= % 2.49% 0.22 ach= % 2.57% 0.17 ach= % 2.64% 0.16 ach= % 2.73% 0.16 ach= % 2.82% 0.16 ach= % 2.93% 0.16 ach= % 3.48% 0.04 ach= % 4.02% 0.21 MMMMMM(%) = NN pp (mm ii ss ii ) ii=1 NN pp (mm ii ) ii=1 CCCC RRRRRRRR(%) = NN pp ii=1 (mm ii ss ii ) 2 /NN pp mm

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