Thermal environment in detached houses with atrium

Transcription

1 Thermal environment in detached houses with atrium Towards proper utilization of atrium space in traditional dwellings Kyo-machiya Chiemi IBA, Shuichi HOKOI & Daisuke OGURA: Kyoto University, Japan Shihono ITO: Takenaka Corporation, Japan

2 2 INTRODUCTION Atrium space in modern houses Atrium space,which is open to rooms or a corridor on the upper floor (sometimes connected to staircase) has been preferred in modern detached houses. An open, spacious and bright space. Residents who stay upstairs and downstairs can easily communicate with each other. However It is quite difficult to design air conditioning system effectively for such modern houses with an atrium.

3 3 INTRODUCTION (continued) Traditional townhouses Kyo-machiya in Kyoto, Japan They generally have atrium space, which is expected to be a path of breeze and daylight. In traditional Kyo-machiya, atrium usually doesn t open to the rooms on the upper floor, but open atrium spaces have increased by renovation. The influences of such atriums on the thermal environment in traditional houses have not been clarified. Exterior of Typical Kyo-machiya Atrium space in Living room (view from 2nd floor )

4 4 INTRODUCTION (continued) Purpose of this study To clarify the effect of atrium space on the indoor thermal environment. Major goal of our research To propose proper ways of living, which can realize both comfortable indoor environment and saving energy. Main target is traditional townhouse. This presentation includes Measurement of indoor environment in two real-scale detached houses with an atrium both in summer and in winter (in modern houses) CFD analysis corresponding to the measurements

5 5 INDOOR ENVIRONMENT IN SUMMER

6 6 INDOOR ENVIRONMENT IN SUMMER Measurement outline Date: August 18 th, 2009 Cite: Two-story gabled house in Kyoto, Japan (House A) Feature: 2 nd floor corridor faces to atrium, 2 nd floor rooms can be open to atrium Air conditioner 2 Air conditioner 1 1 st floor center Staircase Living room 2 nd floor near AC 2 nd floor center Atrium 1 st floor plan 2 nd floor plan South Elevation

7 7 INDOOR ENVIRONMENT IN SUMMER Measurement of indoor environment Measurement patterns Pattern Windows on 1st floor on 2nd floor Air conditioners on 1 st & 2 nd floors 1 CLOSE CLOSE ON Remarks Cooling by air-conditioner (set at 27 C) 2 OPEN OPEN OFF 3 CLOSE OPEN OFF Natural ventilation (Outdoor temperature was kept at about 32 C) expected to bring comfortable breeze to living space

8 8 INDOOR ENVIRONMENT IN SUMMER Measurement of indoor environment Case of Cooling by air-conditioner : Pattern 1 The cooler air from the AC on 2 nd floor flowed downward to 1 st floor. Airflow distribution Temperature profile (Pattern 1) (Cooling set temperature is 27 C.)

9 9 INDOOR ENVIRONMENT IN SUMMER Measurement of indoor environment Case of Natural ventilation: Pattern 2 Airflow distribution Temperature profile (Pattern 2 & 3) Pattern 2 Pattern 3

10 10 INDOOR ENVIRONMENT IN SUMMER Measurement of indoor environment Case of Natural ventilation: Pattern 3 In the case of natural ventilation, the airflow direction mainly depends on the outside wind direction, and changes frequently. Airflow distribution Temperature profile (Pattern 2 & 3) Pattern 2 Pattern 3

11 11 INDOOR ENVIRONMENT IN SUMMER CFD Analysis of indoor airflow The case of natural ventilation was analyzed by using STAR-CD Calculation conditions Standard k-ε turbulence model is used. 40 x 40 x 40 grid cells Boundary conditions: measured data Inlet air: 32 C, 1.0m/s External walls: 32 C, no-slip condition Partition walls: no-slip and no-heat flux conditions N Simulation Model for House A (Pattern 3)

12 12 INDOOR ENVIRONMENT IN SUMMER CFD Analysis of indoor airflow Airflow distribution on 2nd floor for Pattern 3 Main stream occurred along the corridor. Strong airflow observed near the outlet window. Calculated Measured Although there were some difference in the low-air-speed area, calculated directions generally agreed with the measured directions.

13 13 INDOOR ENVIRONMENT IN SUMMER Influence of atrium space on indoor airflow Effect of cross ventilation: Comparison between with and without atrium With Atrium Inlet Window-8 Inlet Window 8 Airflow distribution on 2 nd floor Airflow distribution on 1 st floor Vertical distribution of airflow Outlet Window-1 1 Inlet Inlet Window-8 8 Atrium Without Atrium Breeze in Living space Outlet 1 Window-1 atrium No Atrium

14 14 INDOOR ENVIRONMENT IN SUMMER Summary 1. When the air conditioner was working, the cool air from the upper floor went down to the lower floor. As a result the upper floor was not sufficiently cooled, while the lower floor was overcooled. Such airflows can make the undesirable situation in terms of both indoor comfort and saving energy. 2. When the windows were opened for natural ventilation, effective cross ventilation did not necessarily occur between floors. (This can be partly because the balustrade by the atrium prevented airflow. ) 3. Under certain conditions, more agreeable indoor ventilation might be obtained in the house without atrium. We should consider the negative aspect of natural ventilation The hotter outside air can make the indoor air higher. We should open or close the windows at the proper time.

15 15 INDOOR ENVIRONMENT IN WINTER

16 16 INDOOR ENVIRONMENT IN WINTER Measurement outline Date: January 16 th, 2011 Cite: Two-story gabled house in Kyoto, Japan (House B) Feature: Large atrium, Staircase connected to atrium, Floor radiant heating system installed between 1 st floor and 2 nd floor Staircase Staircase Living room Atrium

17 17 When the doors on 2 nd floor were closed INDOOR ENVIRONMENT IN WINTER 0.14m/s 0.10m/s (410mm high) 0.10m/s 0.14m/s (820mm high) 0.25m/s (1,230mm high) 0.22m/s (1,640mm high) 0.22m/s 0.07m/s (on the beam) Airflows could not be detected on 2 nd floor. Measurement of indoor airflow 0.05m/s (on the beam) Wind speed increased. When the doors on 2 nd floor were open corridor Inner garden 0.25m/s (410mm high) 0.25m/s 0.41m/s 0.41m/s (820mm high) 0.35m/s (1,640mm high) 0.35m/s 0.19m/s (1,800mm high) 0.05m/s (1,000mm high) 0.22m/s (2,650mm high) 0.14m/s (on the beam) 0.05m/s (on the beam) 0.40m/s (100mm high) 0.05m/s (550mm high) 0.17m/s (on the beam)

18 18 3. INDOOR ENVIRONMENT IN WINTER CFD Analysis of indoor airflow Simulation Model for House B Atrium Closet クローゼット 吹抜け Corridor 廊下 Room 洋室 1 1 Room 洋室 2 2 Kitchen Dining room Living room Japanese room 1 st floor plan Living リビング room Room 洋室 3 解析モデル ( 住宅 C) Wall surface temperature [ C] Japanese 和室 room 1 st floor 2 nd floor floor wall ceiling floor wall partition ceiling Room 1 Room 2 Staircase Atrium Closet Room 3 2 nd floor plan

19 19 INDOOR ENVIRONMENT IN WINTER CFD Analysis of indoor airflow Airflow distributions 1 st floor 2 nd floor Vertical Temperature distributions 1 st floor 2 nd floor Vertical

20 20 3. INDOOR ENVIRONMENT IN WINTER Summary 1. A cold draft occurred through the atrium and the staircase even though there was little vertical temperature difference. 2. The atrium and the staircase should be separated to prevent this cold draft.

21 21 CONCLUSIONS The influence of an atrium and a staircase on the indoor thermal environment both in summer and in winter was investigated mainly concerning airflow distribution. Atriums and staircases don t necessarily have good influence under certain conditions. Particularly in winter, the combination of atrium and staircase can cause undesirable cold draft. If some partitions are installed in proper position and are operated reasonably, such undesirable airflow can be avoided.

22 22 Now we re doing measurement in traditional townhouses in Kyoto to propose the reasonable utilization technique of atrium space. Thank you for your attention!

23 23 Supplemental materials

24 24 1. INTRODUCTION (continued) A major goal of our research is To propose proper ways of living, which enable comfortable and energy-saving indoor environment in traditional dwellings. In this paper We focus on the effect of atrium space on the indoor thermal environment, particularly focusing air flows in a house. 1. Indoor environmental factors (temperature and airflow rate) were measured in two real-scale detached houses with an atrium. 2. The airflow and the temperature distributions in the house were simulated by using CFD analysis. 3. The analysis model was verified by comparing the calculation results with the measurement results. 4. By using this analysis model, the cases with and without an atrium were calculated.

25 25 CONTENTS 1. INTRODUCTION 2. INDOOR ENVIRONMENT IN SUMMER Measurement of indoor environment CFD analysis of indoor airflow 3. INDOOR ENVIRONMENT IN WINTER Measurement of indoor environment CFD analysis of indoor airflow 4. DISCUSSIONS 5. CONCLUSIONS

26 26 2. INDOOR ENVIRONMENT IN SUMMER CFD Analysis of indoor airflow Calculated temperature distribution in Pattern C 31.3 C 32.0 C 31.3 C 31.4 C 31.4 C 30.5 C 31.4 C 31.4 C 30.2 C Vertical Horizontal

27 P1 (Living room) P4(Japanese style room) P3(Kitchen) P2(Dining room) 3. INDOOR ENVIRONMENT IN WINTER Temperature[ C] P6(Utility) P5(Entrance) Measurement of indoor temperature :30 11:00 11:30 12:00 P11(near window) 12:30 13:00 Time Outside 13:30 14:00 14:30 15:00 P7(Room 1) 15:30 20 Temperature[ C] P8(Room 2) P9(Room 3) P10(Closet) Outside 0 10:30 11:00 11:30 12:00 12:30 13:00 Time 13:30 14:00 14:30 15:00 15:30