Thermowall insulated sandwich panels offer the chance to drive down a building's energy consumption to levels that are not possible with traditional construction and yet still take advantage of the thermal mass effect.
What is thermal mass?
Thermal mass is the ability of a material to absorb heat. A lot of heat energy is required to change the temperature of a high-density material like concrete. High thermal mass low conductivity materials act as thermal sponges, absorbing heat during the summer to cool the building, and store heat from the sun or heaters to release it at night.
Why is it important?
The thermal capacity of concrete structures can be utilised to improve the energy efficiency of buildings. Compared to air conditioning, Active Fabric Energy Storage reduces carbon dioxide emissions by up to 50%. About 90% of the environmental impact from buildings is from heating cooling and lighting, and only about 10% is from the embodied energy used to produce the fabric of the building itself (taken over a 60 year life-cycle).
Which bits matter?
It is essential that the thermal mass of the material is exposed within the fabric of the building. In other words, the ability of the concrete to absorb energy would be severely compromised by placing a suspended ceiling made from a less dense material in front of it.
By adopting an environmentally responsible attitude towards the specification, design, and construction of our building, infrastructure and civil engineering projects, we can choose materials for all the right reasons and our choice can have beneficial effects all the way through the life-cycle of a building or structure.
What are Thermowall Panels?
Thermowall Panels comprise of two layers of concrete with a layer of insulation sandwiched in between. They are connected together with non-metallic low conductivity ties to ensure that the panels remain thermally efficient and there is no ‘cold bridging’ between the layers.
Either as part of Crosswall Construction, or as fixed to a steel or concrete frame, Thermowall insulated sandwich panels offer the chance to drive down a building’s energy consumption levels compared to traditional construction.
They achieve this by utilising the following factors inherent in their design:
- Thermal Mass
- Good Insulation Values
- Excellent Air Tightness
- No Cold Bridging
Traditionally, the inside and outside skins of walls are connected with metallic ties which allow thermal bridging from the external face to the inside of the building. CCP’s Thermowall Insulated Sandwich Panels replace the metallic ties with “Thermomass” (Insulating Connector System used in CCP’s Thermowall panels) composite ties with a conductivity value of 0.3W/m2K enhancing the performance of the insulation.
The types of ties, usually known as connectors, do not have the same constraints as blockwork ties and hence insulation thicknesses can be increased. There is the potential to achieve ‘U’ values of 0.1W/m2K or below. The environmental benefits of this system over the life cycle of a building are enormous.
Furthermore, Thermowall insulated sandwich panels, like all CCP Crosswall Construction products are made with CCP’s environmentally friendly concrete called “Ecocrete” where over 80% of the content of the panels is secondary sourced, and can help to contribute to BREEAM excellence with an Ecopoint score of 0.02.
The structural component of a Thermowall is the inner skin. This is normally 150mm thick and is reinforced with steel to take the various loads applied to the panel.
The outer skin provides protection from the environment and can be produced to a variety of different finishes to meet the designer’s requirements, and these need not be limited to traditional architectural concrete finishes.
The outer skin is thinner, typically between 50 and 75mm thick and requires minimal reinforcement which can be either steel or polypropylene fibre.
The whole panel can be attached to steel frames using simple steel brackets.
Alternatively it is possible to join panels so that they act compositely forming a monolithic building avoiding the need for a separate frame as part of a crosswall construction.
The insulation thickness can be varied to suit the specification of the designer, but with this design much greater thicknesses can be provided.
For instance, ‘U’ values of 0.1W/m2K or below are achievable and when coupled with virtual zero cold bridging and excellent air tightness will result in very low energy loss from the building through the walls.
INTERSTITIAL CONDENSATION ELIMINATION
Thermowall insulated sandwich panels can be either fixed to a steel or concrete frame or be part of an overall crosswall construction with either solid panels with insitu stitched corners or as part of a twin (double) wall construction.
(see crosswall construction brochure)
Typical details are shown below connecting to a steel frame using rolled steel angles welded to the columns and bolts connecting the angles to cast in threaded sockets in the panel.
Similar connections can be used for concrete frames with the angles bolted onto sockets resined into holes drilled into the frame or into cast in sockets.
Typical connection detail – Plan Typical connection detail - Section
Thermowall insulated sandwich panels are cast face down on flat steel pallets and are manufactured in CCP’s state of the art carousel plant and are set out direct from the CAD drawing by a robotic plotter.
Predrilled insulation is then placed on top of this layer and then special non-metallic ties are inserted.
The complete range of architectural finishes are available with this product including reconstituted stone and brick cladding as well as a range of cost effective durable applied finishes.
Reinforcement is then placed in the mould, and concrete for the inner wall is then poured forming the other layer of the sandwich.
The panels are then tilted up and lifted away. This ensures that only the minimum amount of reinforcement is necessary, reducing costs and wastage.
Thermowall panel walling enables unprecedented speed in sealing the building envelope, reduces lifetime energy costs, can be left untreated, no external scaffold on the building and low maintenance costs.