A platform for research: civil engineering, architecture and urbanism
A platform for research: civil engineering, architecture and urbanism
Using simulated co-heating tests to understand weather driven sources of uncertainty within the co-heating test method
The so-called performance gap between designed and as-built building performance threatens to undermine carbon reduction strategies in the built environment. Field measurements to date have indicated that the measured as-built fabric heat loss of tested UK buildings is consistently higher than design values, often considerably so. Currently, our lack of knowledge over the extent of this gap, and the processes that cause it, is compounded by a lack of robust post-construction evaluation tools. Much of this post-construction evaluation work is based, in part, on the use of co-heating tests: a method utilising an energy balance to determine the heat loss across the entire building envelope, defined by the heat loss coefficient (W/K). However, the errors associated with co-heating are not well understood or typically addressed in the literature. Furthermore, the test procedure requires a building to be unoccupied for two to three weeks and is therefore often cited as costly and unsuitable both for developers and as a policy tool. In order to improve the application of this test method it is crucial firstly to understand the sources of uncertainty in co-heating tests and the ‘steady-state’ energy balance they are based upon. However, with a small database of tests performed to date it is difficult to discern these sources of error. This paper presents the results of a method using simulated co-heating tests to show how key weather variables influence the co-heating result and generate uncertainty and bias. In particular the effects of short-wave solar and long-wave sky radiation are presented. Improvements to the co-heating method can be derived from this; in particular the need to consider when dwellings should be tested to avoid large solar-generated errors and the importance of a accurately calculated solar aperture. Recommendations also include the local measurement of sky radiation to avoid outlying data points, bias in the measurement and discrepancies when comparing design and as-built heat loss.
Using simulated co-heating tests to understand weather driven sources of uncertainty within the co-heating test method
The so-called performance gap between designed and as-built building performance threatens to undermine carbon reduction strategies in the built environment. Field measurements to date have indicated that the measured as-built fabric heat loss of tested UK buildings is consistently higher than design values, often considerably so. Currently, our lack of knowledge over the extent of this gap, and the processes that cause it, is compounded by a lack of robust post-construction evaluation tools. Much of this post-construction evaluation work is based, in part, on the use of co-heating tests: a method utilising an energy balance to determine the heat loss across the entire building envelope, defined by the heat loss coefficient (W/K). However, the errors associated with co-heating are not well understood or typically addressed in the literature. Furthermore, the test procedure requires a building to be unoccupied for two to three weeks and is therefore often cited as costly and unsuitable both for developers and as a policy tool. In order to improve the application of this test method it is crucial firstly to understand the sources of uncertainty in co-heating tests and the ‘steady-state’ energy balance they are based upon. However, with a small database of tests performed to date it is difficult to discern these sources of error. This paper presents the results of a method using simulated co-heating tests to show how key weather variables influence the co-heating result and generate uncertainty and bias. In particular the effects of short-wave solar and long-wave sky radiation are presented. Improvements to the co-heating method can be derived from this; in particular the need to consider when dwellings should be tested to avoid large solar-generated errors and the importance of a accurately calculated solar aperture. Recommendations also include the local measurement of sky radiation to avoid outlying data points, bias in the measurement and discrepancies when comparing design and as-built heat loss.
Using simulated co-heating tests to understand weather driven sources of uncertainty within the co-heating test method
Stamp, S (author) / Lowe, R (author) / Altamirano, H (author)
2013-01-01
In: eceee Summer Study proceedings. (pp. pp. 2049-2055). eceee (2013)
Paper
Electronic Resource
English
DDC:
690
Tests for heating plants in mild weather
| Engineering Index Backfile | 1919
The Impact of Different Weather Data on Simulated Residential Heating and Cooling Loads
| British Library Conference Proceedings | 1998
The Impact of Different Weather Data on Simulated Residential Heating and Cooling Loads
| British Library Online Contents | 1998
Curing device for cold weather concrete using a heating element
| European Patent Office | 2023
Curing device for cold weather concrete using a heating element
European Patent Office | 2024