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Current
Completed
 
 
Current thermal research
The use of BMS to control facades
The use of double facades to facilite on demand ventilation
MODCELL: an innovative straw bale building system
Hempcrete

The use of BMS to control facades

Status
Starting 1 January 2007


Duration
18 months


Partners
Centre for Window and Cladding Technology (lead)
Council for Aluminiun in Building
Carillion
Faber Maunsell
Max Fordham
SE Controls
Velfac


Objectives
There are two objects to this research.  One is to identify barriers to the use of BMS controlled automated facades and to report on the ways that these barriers may be broken down.  The other is to look at additional functionality that will tip the balance in favour of using BMS controlled automated facades.


This project will:
•    Review operable components of facades that are currently available;    
•     Review the limitations of current control strategies for facades, particularly the control of glare;
•     Review the current actuator technology including how it interfaces with BMS and its reliability;  

•    Report on the process of designing buildings with BMS controlled automated facades, based on interviews with designers;
•    Report on the construction of buildings that incorporate BMS controlled facades;    
•    Investigate the additional functionality that can be achieved by using sensors in different combinations, especially to develop an actuator that can be used for controlling glare and limiting solar over heating;
•    Produce two reports.  One aimed at clients and architects to show the benefits of automated facades and how to design/specify them, and the second for contractors explaining how these systems are integrated with one another and with the façade and the building.

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The use of double facades to facilite on demand ventilation


Status
Starting 1 January 2007


Duration
24 months


Partners
Allies and Morrison
Bennetts Associates
Centre fro Window and Cladding Technology (lead)
Council for Aluminium in Building
Carillion
Hoare Lea
Sir Robert McAlpine


Objectives
The objective of this work is to establish virtual precedents of the use of double facades that will provide a pressure moderated plenum from which air can be drawn for demand controlled ventilation. 


This project will:
•    Undertake a desk study of wind events in the UK.  This will include a review of the minimum conditions required to activate ventilation on demand;   
•    Postulate façade geometries for a number of building layouts to optimise the use of the thermal stack effect;
•    Model the performance of a pressure moderated plenum of the double façade using CFD analysis.  Different geometries will be looked at;   
•    Study existing building projects to determine the typical demands for ventilation and other factors controlled by the building envelope including daylight, solar gain, and heat transfer;    
•    Determine rules for use at the outline design stage using the information found above;   
•    Produce two reports.  One will be written for use by clients and architects and will present information required to allow the inclusion of an effective double façade.  The other will present an engineering methodology for use by the cladding and building services engineers.

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 MODCELL: an innovative straw bale building system


Status
Starting 1 January 2007


Duration
24 months


Partners
Agrifibre Technology Ltd
Centre for Window and Cladding Technology
Eurban Limited
Integral Structural Design
Lime Technology Ltd
University of Bath (lead)
White Design


Objectives
This project aims to further develop an innovative sustainable building system using straw bale construction technology.  Modcell building and cladding panels comprise a timber frame in-filled with straw bale insulation.  The bales are compacted and reinforced with steel bars and protected with lime or cement based plaster coats.  The project seeks to investigate and perfect the manufacturing methods and develop robust design data.  The study will comprise laboratory and analytical research investigations, design studies, environmental performance modelling, life cycle assessment, and in-situ monitoring of prototypes.


CWCT are involved in the thermal analysis and condensation risk assessment of the constructions.  We will be carrying out:
•    A literature review of material properties to obtain representative values for the thermal conductivity and vapour resistivity of straw bales;    
•    One-dimensional static thermal analysis and condensation risk assessment in order to investigate the effect of bale and render thickness;
•    One-dimensional dynamic thermal analysis and condensation risk assessment in order to investigate the effect of bale and render thickness;    
•    Two- or three-dimensional thermal/moisture transfer analysis at the junctions between the Modcell panels and windows and doors;   
•    Three-dimensional thermal/moisture transfer analysis at localised thermal bridges.

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Hempcrete


Status
Current


Duration
3 months


Partners
Lhoist UK
Lime Technology Ltd
University of Bath


Objectives
Hemp construction is considered environmentally friendly and highly sustainable.  The hemp can be mixed with lime to form ‘Hempcrete' and can then be used as a building material in place of brick/blockwork.  A project at Haverhill in Suffolk built two houses out of Hempcrete and these will be used as the basis of some of the following work.  These houses were identical to some traditionally constructed houses so comparisons between the two could be made.


CWCT will be studying the thermal performance of the Hempcrete construction.  This will include:

•    Reviewing the construction details and comparing them with those of a traditional building with the same geometry and usage;
   
•    Assessment of all the building elements by either simulation or calculation;
•    Dynamic heat transfer analysis to compare the temperature variation of hemp wall over the course of 24 hours with that of a brick-block wall with identical geometry;    
•    The effect of the surface finish.  Different finishes will result in a different surface emissivity, and affect the therefore the U-value;    
•    Looking at, and comparing, the heat loss due to air leakage through both houses at Haverhill;   
•    Inputting data obtained previously into whole building energy consumption software to calculate the overall CO 2 emission rate for the hemp house and the brick-block house at Haverhill.


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