ARPAN JOHARI. Architect. 13/08/10 AW Design. Ahmedabad

Transcription

1 ARPAN JOHARI. Architect

2 THERMAL MASS Thermal mass (or thermal capacitance) is defined as the ability of a body to store heat

3 THERMAL MASS Thermal mass is also known as Fabric Energy Storage, FES (The Concrete Centre. 2005), thermal mass is a less exploited and effective sustainable alternative to air-conditioning for combating the temperatures. Thermal mass of the fabric, i.e. concrete or ground is effective in maintaining the desired comfort levels. They work on a principle that buildings with high thermal mass have a slow response rate to changes in ambient climate. It benefits the buildings particularly in summer times, when concrete absorbs internal heat gains to avoid over heating. This heat sink builds-up towards accumulating higher temperatures at evening times. Evening cooling of these buildings helps take off this excessive heat build-up anditfurthermovesontothenextdaycycle

4 THERMAL MASS Stabilising effect of thermal mass on internal temperatures Source: Termodeck,2005

5 THERMAL MASS Thermal mass works on a simple principle of the slow response of concrete to changes in the weather conditions. This aids in reducing peak temperatures especially during summer days when the internal heat gains are absorbed by concrete which prevents over heating. This property of high absorbance and low transmittance can delay the onset of peak temperatures by uptosix hours. This property is known as Thermal Lag, This typically in an office environment happens in late afternoons of when the occupants have left.

6 THERMAL MASS Thermal Lag Source: Termodeck,2005

7 THERMAL MASS Case Study; TermoDeck TermoDecksystem uses high thermal mass of hollow concrete slabs for delivering comfortable results. The system comprises of a fan assembly, ducting and purpose built for concrete slabs. Through these slabs, warmed or cooled fresh air is distributed. Fresh air supplied to the system passes through channels in the tube, which facilitate prolonged contact between air and the slabs. These slabs exhibit passive cooling or heating by either taking or adding energy to the system.

8 Case Study - TermoDeck TermoDeck using principles of Thermal mass Source: Termodeck,2005

9 Case Study - TermoDeck Source: Termodeck,2005

10 Case Study - TermoDeck The system reacts to thermal loads in four ways: Summer days: warm ambient air is cooled when it enters the pre-cooled hollow slabs. This cool concrete also absorbs heat generated from lighting machinery, people and re-radiated solar gains Source: Termodeck,2005

11 Case Study - TermoDeck Summer nights: at night times, outdoor air is blown into the hollow slabs. This assists cooling down the building frame to the next day. Source: Termodeck,2005

12 Case Study - TermoDeck Winter days: it helps during the cold winters as the tightly sealed and highly insulated building envelope helps prevent heat loss from inside the building. Heat from the rooms is extracted from them by using extraction fans and is passed back to the slab which in turn conduits it in the other activityareas Source: Termodeck,2005

13 Case Study - TermoDeck Winter nights: this works by shutting the system at night. The daytime heat gains are slowly distributed. If the building cools down prematurely, which might happen occasionally, the sensors in the ceiling would turn on the heating system. This would take of the load from the conventional heating system and would hence assist in reducing energy related costs.

14 Case Study - TermoDeck Stability of internal temperatures in a TermoDeck building Source: Termodeck,2005

15 Advantages - TermoDeck Reduces the capital costs of building materials by using modular components. Low complexity of services leads to lower maintenance costs. Great reduction in the amount of using ancillary mechanicals like fans and chillers. Reduces the need for false ceilings and ceiling voids. This leads to reduction in storey heights Reduction in moving parts outside plant rooms Non complicated and short commissioning period Different temperature zones do not demand for dedicated climate control systems. One slab takes care of temperatures and ducting for upto 16 meters

16 Advantages - TermoDeck Slabs provide both, radiant and conductive heating/cooling, owed to the high thermal mass Service and cleaning points allow for easy and cheap cleaning Running costs as compared to air-conditioned buildings is lower by upto 46% Maintenance costs are greatly reduced. Upto 13% for air-conditioned buildings and upto 33% for naturally ventilated buildings Thermal mass contributes to a great extent in regulating the building climate as compared to buildings with mechanical ventilation

17 Case Study - TermoDeck Annual Costs Source: Termodeck,2005

18 Case Study - TermoDeck Energy Consumption Source: DETR Report

19 Advantages Reduced carbon dioxide emissions in the entire life cycle Heat recovery of upto90% from extract air stream leads to a greatly reduced energy consumption pattern. No temperature draughts. All the year uniform temperature stability Fresh air is tempered within in the system, as compared to using an expensive plant for the same Fresh filtered air is supplied well in excess of the recommended 8L/second. Exposure of the slabs to both, air and room temperatures helps to get a better temperature stabilization No need for radiators eliminates further problems of energy supply and maintenance

20 Advantages It is virtually unobtrusive, both visually and physically on building interiors and exteriors Opening windows does not add any further loads to the system Virtually no operational sound of the system. Further the sounds produced by the fans are damped by the dense concrete slabs. It is highly effective in the Hz frequency range Acoustical Performance Source: Termodeck,2005

21 Case Study - TermoDeck Energy inputs by various systems Source: Termodeck,2005

22 Case Study - TermoDeck Life cycle costs over 25 year period Source: Termodeck,2005

23 Thank you QUESTIONS 13/08/10 AW Design. Ahmedabad

24 DEBATE 13/08/10 AW Design. Ahmedabad