Webinar - Oversized air-conditioning systems and overcooled buildings in hot and humid climates

January 13th 2016, MIDDAY GMT (8pm Singapore, 5.30pm India) 

Webinar - Oversized air-conditioning systems and overcooled buildings in hot and humid climates.

Professor Chandra Sekhar will explore why air-conditioned buildings in hot and humid climates are often so cold that one gets reminded to bring a jacket when going to the office.

He will consider the consequences of raising the set point temperatures as a means of improving the situation and expose some of the engineering challenges that necessitate a relook at the way air-conditioned buildings in such climates are designed.In doing so he will review some of the fundamental issues of cooling and dehumidification facing the HVAC designer and the inevitable and inherent design of an oversized system and its undesirable consequences in terms of an overcooled indoor environment at peak and part loads in hot and humid climates.

There will be discussion on solutions for creating a more thermally comfortable and healthy indoor environment that can also save energy. 

Book your webinar place for free at: 

https://attendee.gotowebinar.com/register/1480876507030471938

Source: CIBSE - ASHRAE Group Newsletter 

http://www.cibseashrae.org/

The Importance of Thermal Bridging

    A typical dwelling built to 2006 standards loses more than 30% of its heat through junctions and around window openings by a process called ‘thermal bridging’.

   For the first time in 2013, UK Building Regulations began to measure heat loss through junctions, this is measured by Y-values (also known as ‘psi’ values). The Y-value in each SAP assessment has a big effect on build materials and cost. If you don’t understand Y-values in your build, you may be paying unnecessary costs.

Thermographic Image Showing Heat Losses Through The External Walls

It is important to familiarise ourselves with terms such as:

• The definition of a thermal bridge
• Types of thermal bridges (repeating, non-repeating and geometrical)
• Psi (ψ) values
• Methods of calculation (1-D, 2-D and 3-D)
• Sequencing of construction processes and examples of common occurrences of thermal bridging.

 

Thermographic Image Showing Heat Loss From Balconies

 

    Thermal bridging can have a significant impact on the thermal and energy performance of the building envelope. In the past, when dwellings were relatively poorly insulated, thermal bridging had little influence on the overall thermal performance of the building. However, as dwellings have become better insulated, the relative importance of thermal bridging has increased. In very well insulated dwellings, the proportional effect that thermal bridging can have on the thermal performance of a dwelling can be significant.

 

Thermal Bridging Calculations For a Steel Structure

 

 

   For example, in a notional semi-detached dwelling (89m² floor area) with a total fabric heat loss of just over 90W/K and a y value of 0.08 (roughly equivalent to a 2006 Part L1A compliant dwelling), then thermal bridging is likely to account for 16% of the dwellings total fabric conduction heat loss (see figure below). If no additional measures are taken to improve thermal bridging beyond this level (i.e. y value remains at 0.08) but the total fabric heat loss reduces by 25% by 2010 and 44% by 2013, then thermal bridging could account for almost 30% of the dwellings total fabric conduction heat loss by 2013.

 

 

   Even when measures are taken to reduce thermal bridging, in very well insulated dwellings, thermal bridging can still account for a significant proportion of the overall fabric conduction heat loss (see figure below).

 

     

 

I   n addition to an increase in fabric conduction heat loss, thermal bridging can also result in:
• An increase in solar heat gains during the summer
• Reduction in internal surface temperatures
• Cold spots occurring within the building
• An increased risk of both surface and interstitial condensation, which may result in mould growth and pattern staining
• Reduction in indoor air quality (due to condensation and mould growth)
• Damage to building components

A   lthough the aim, particularly in low and zero carbon dwellings, should be to try and design and construct dwellings that are thermal bridge free, it is important to realise that it is not generally possible to eliminate thermal bridging altogether. Instead, efforts should be made to minimise thermal bridging as much as is possible.

 

Sources:

http://www.leedsbeckett.ac.uk/teaching/vsite/low_carbon_housing/thermal_bridging/introduction/index.htm

 

 http://www.schock-blog.com/wp-content/uploads/2014/03/thermal-Performance-steel-structure.jpg

 

CPDs and Sustainable Retrofit

   Undergraduate studies and postgraduate studies are never enough if a professional wants to be up-to-date with the market they are involved into.

 

   For architects, engineers and builders, CPD seminars or a regular basis are a must, as they help us catch up with the latest news in the industry, master in innovation and understand how the things that we design work.

 

   As I am personally keen on green design and improving energy performance of buildings, I do frequently look up and read, read, read endlessly about new building solutions, materials, science innovations and so on.

 

   What is best about this is that I can share things I find interesting with you lot, hence the purpose of the Eco-Review BlogSpot (and its facebook page extension...)

 

   In the link at the end of this post, there is an online CPD video seminar to watch, which gives a good insight on Cellular Glass Insulation and how this is applied to all the main parts of a building.

 

   Insulation materials vary so much and it often becomes confusing as per what is suitable where and for what reason.

   For instance, not all insulation materials have a low carbon footprint - in fact usually these tend to provide a lower performance that the oil-based or the mineral ones, but whatever the case, we need to know that the materials we use will perform as we expect them to, as long as they are used where they are supposed to.

   We also need to look at their physical properties, such as their vapour permeability, their compressive strength, the way these are installed, their cost, ease of handling, health implications in the manufacturing process, during installation and post-installation. Physics may be overwhelming for some designers, but it is an essential part to look at, as materials' science is directly related to buildings and therefore, if something is out of our field of knowledge, we should always seek for advice from a specialist and bring them on board in the design process.

 

Source:

http://www.ribacpd.com/foamglas/05864/cellular-glass-insulating-the-whole-building/287539/movie

 

'Refurbished House' tests four-in-a-block retrofit

BRE Ravenscraig enables different refurbs to typical Scottish building type. 

A project is demonstrating retrofit solutions for some of the most energy inefficient homes across Scotland and the UK. The newly-built Refurbished House, which has been constructed at the BRE Innovation Park @Ravenscraig, in Scotland, is a recreation of a ‘four in a block’ building, with two apartments on the ground floor and two on the first.

Developed specifically for retrofit, the project has been delivered by BRE Scotland, Edinburgh Napier University and Historic Scotland. It is designed by Kraft Architecture and Hannah Read Consulting Engineers and constructed by contractor Cruden. The house enables robust assessments to be made of cost effective upgrading solutions for walls, windows, roofs and services for this building type. There are estimated to be 265,000 of the ‘four in a block’ home types in Scotland but their build style is similar to cavity block walls found in 3m homes in England. 

The block of homes allows different technologies and approaches to be compared. The upper homes are being equipped with solar technology, while lower homes feature underfloor heating. One is being retrofitted with minimum disruption to mimic tenant occupation, while another is being retrofitted as an empty unit.

BRE is also developing a BRE RetrofitLab app to aid home retrofit, and help users to select retrofit materials and solutions.

Watch the video

Source: http://www.building4change.com/article.jsp?id=2444#.U8gPqvldWKJ 

Report from – Jo Smit 13/7/2014

Why is London ignoring its PV potential?

Green report calls on mayor Boris Johnson to improve capital’s solar uptake

High installation costs, landlord and tenant issues and the prevalence of apartment blocks are among the factors holding back uptake of solar photovoltaics (PV) on London’s buildings. The amount of generated solar electricity has doubled in the UK over the last year, but London has the lowest uptake of solar panels of any region on mainland Britain.

A new report by Green Party member of the London Assembly Jenny Jones considers solar potential in the capital, plus key barriers and possible solutions. It recommends the formation of a dedicated City Hall team to help businesses, tenants and communities install solar on the empty rooftops of London’s commercial and industrial businesses, supermarkets, flats, schools, transport and public buildings.

Findings in the report include:

Only one in 260 London households have installed solar panels. The South West of England has eight times the installation rate of London

London has the potential to supply a fifth of its electricity needs from solar PV

There are wide variations in take up rates between London boroughs. Waltham Forest has one solar PV installation for every 88 homes, while neighbouring Enfield has one per 362 homes.

Jones called on London mayor Boris Johnson to take action to improve PV uptake in the capital, for example by incorporating rooftop PV into such existing retrofit programmes as its RE:NEW and RE:FIT. Jones said: “Given that solar photovoltaics have the greatest potential of any renewable electricity generating technology, it is astonishing that the mayor is not promoting and helping London’s residents, businesses, schools and communities to harvest solar electricity from their underused and empty roof tops”

The report, London is ready for a brighter future – Solar generated electricity – Why are we missing out? can be downloaded here.

Source: http://www.building4change.com/article.jsp?id=2440#.U8gPrPldWKJ

Report from – Jo Smit 10/7/2014

High hopes for a sustainable future for Newcastle

New innovation hub boasts one of the UK’s tallest living walls

A 27m-high living wall offering wild strawberries, seagrass and sanctuary for small birds has been installed as part of the build programme for a new sustainable innovation hub in Newcastle. The vertical garden forms a key focal point at Science Central, a 24-acre development currently being constructed by Newcastle Science City, a partnership between Newcastle City Council and Newcastle University.

Designed and engineered by Faulkner Brown Architects in conjunction with Land Use Consultants, ANS Group Europe, Mott MacDonald and Sir Robert McAlpine, the wall measures around 366 sq m in area and contains more than 35,000 plants. The aim was to create an example of urban sustainability in order to encourage sustainable innovation and motivate other organisations to follow suit, as well as consider the possibility of relocating to the region.

The team constructed a series of rails on the side of the seven-storey Core building, the first to be completed on the science park, which will provide 2,750 sq m of flexible office space for technology and science-based businesses. Boxes of plants were slotted into the rails before being linked to an irrigation system. The planting took two weeks in total, from fitting the first rail to potting the final plant.

“We have received a really positive reaction to our living wall,” said Fiona Standfield, director of Newcastle Science City. “It is quite unique and is the first and largest of its kind known to have been installed this far north." It is hoped that the wall will attract a wide range of wildlife to the local area. "We’re also installing 'bee hotels’ on the building which will encourage even more flora and fauna,” explained Standfield.

The building will be surrounded by wildflower and grass meadows, connecting Newcastle’s West End directly to the city centre. Other sustainable features including a planted sedum roof, rainwater harvesting and low energy LED lighting contribute to its BREEAM Excellent rating that was awarded at the design stage.

The Core building is set to open for business in November 2014. For more, visitwww.newcastlesciencecentral.com

Source: http://www.building4change.com/article.jsp?id=2439#.U8gPsPldWKJ

Report from – Keri Jordan 10/7/2014

It's a mud mud mud mud world: Herzog & de Meuron design Europe's largest rammed earth building

Herzog & de Meuron have done a number of buildings for Ricola, the Swiss cough drop company with the really annoying commercial. Now they have completed the Kräuterzentrum, or herb processing center, where the drying, cutting, blending and storing of the locally grown ingredients takes place. The walls of the building are rammed earth, built by TreeHugger regular Martin Rauch of Lehm Ton Erde (Loam Clay Earth).

There are a lot of benefits to building with rammed earth. The thick walls have a lot of thermal mass, which stabilizes the temperature and humidity, significantly reducing the need for air conditioning. It is made from local dirt sourced less than 10 kilometers away, prefabricated in a temporary factory in a nearby town. “No elements are used other than natural and organic earth from Laufen. This is especially energy-efficient,” asserts [CEO] Felix Richterich.

The architects describe the process:

Clay, marl and material excavated on site are mixed and compacted in a formwork and then layered in blocks to build the walls. Thanks to the plasticity of the loam, the seams can be retouched giving the overall structure a homogeneous appearance. To arrest erosion caused by wind and rain, a trass mortar achieved mixing volcanic tuff (trass) with lime, is compacted every 8 layers of earth directly in the formwork.

Those white lines of mortar act as overhangs and stop the earth from washing away. In North America many rammed earth buildings have cement added to the mix of earth to preserve it, turning it almost into concrete; here, the walls are pure dirt inside and out. Martin Rauch notes that mud isn't just for huts anymore:

Many people think that nowadays loam is only used in developing countries to build the most basic huts. However, the Ricola Herb Center makes a strong statement about future perspectives and the positive qualities which loam construction can have in Europe as well.

Rammed earth is such a wonderful material, it doesn't get any more natural. Prefabricating it inside instead of hammering it into formwork on site probably has benefits in terms of consistency and less worry about rain getting on it prematurely. However those panels are going to be heavy.

Source: http://www.treehugger.com/green-architecture/its-mud-mud-mud-mud-world-herzog-de-meuron-design-europes-largest-rammed-earth-building.html