Please find below the Climate CoLab judging results for your Proposal.

Finalist Evaluation

Judges' Ratings
Novelty:
Feasibility:
Impact:
Presentation:

Judges' Comments
The proposal goes beyond looking at just the technical challenges alone, and outlines a clear plan for putting together a process that looks at the issue in a holistic fashion.

Great combination of innovative use of resources along with a highly developed program and understanding of what it will take to make it happen.

Creative use of waste materials (especially foam plastics) and targeting of a growing niche market with an energy efficient lower priced home. Approach also seems suited to charities and aid organisations for housing and other buildings, eg health care. Disaster resistance also valuable.

Semi-Finalist Evaluation

Judges' Ratings
Novelty:
Feasibility:
Impact:
Presentation:

Judges' Comments
Comments from Judge 1:

Great example of how a high performance building can be accomplished using a low tech approach.

Comments from Judge 2:

You explain a lot of the practical aspects of the approach, but quite a few issues are unclear. For example, the solar hot water service in the picture would not provide much heat in winter in many locations - so is it adequate to provide both space heating and hot water? Also you mention using tap water to cool the walls in summer but then say rain and water are scarce in Lesotho. How much water is needed, and where does it come from? Also, cement can be expensive, as can all the plumbing components you use. Can the poor actually afford this house? The use of waste materials for insulation seems good - does the masonry wall address the fire and pollution risk (when burning) of the scrap plastic foam insulation? How does the need for training of builders compare with other low emission options? I need more evidence to convince me that this approach has potential to succeed in mass markets in poor countries, even though it sounds as though it produces comfortable homes.

Discussion area


sultanj




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Proposal
creator

In response to the comments from judges, please see summarized response below:

- More than one solar water heater (SHW): W agree that if we can afford to provide more solar water heater it would be preferable for some locations. But we are dealing with a poor community that has a limited budget and may be able to add additional (SHW) in phases and as finances permit. However SHW are relatively cheap - the one we have on the roof cost us about US $400 (installed). It is cheaper as it does not have a built-in heating element. However it is winter in Lesotho right now, we are inconstant touch with the Sisters running the facility, and even though the temperature at night is around 26F to 28F, they tell me that the house stays warm and does not need space heaters or supplementary heat. If they experience cloudy weather they do need supplementary heat for short periods. We figure we will need supplementary heat for 30 of the the 365 days in a year.

-- we have 75 gallon water tank that is buried under the floor and is insulated. The heating system is based on a closed loop system, so there is no exchange of fluids- only exchange of heat with a heat exchanger. So radiant floor heating is a hydronic system using plastic (pex) pipe and heat is transferred in the heat exchanger. The hot water heating system is a closed loop, with parts exchanging heat made of copper, and they transfer the heat to water in the heat exchanger - through conduction. Each time 4 elderly take shower the water travels heating the walls and then the tepid water used for shower. A second line, direct feed from SHW, allows you to temper the water temperature. Piped water, and rain harvesting is practiced extensively, is available. However it does not rain much. People who live in shelters still need to shower and need water for plumbing. It is this same water which is utilized in the heat exchanger. None of the water is wasted.

- the cement utilized is about 70% less than comparable masonry structure. Masonry blocks have to have a minimal strength of 2000 psi to 1500 psi as they have to be designed not only for load bearing but also to resist breakage during transportation etc. Cement ends up using about 15% to 20% of the masonry block by weight. Majority of our walls are infill walls, non-loadbearing, are roughly a lean mix with strength of about  500 psi to 750 psi, and cement is less than 5% to 7% of the lean concrete by weight, and after taking the insulation as a factor less than 2.5 to 4% by volume of wall.  So we are using a lot less than cement compared to masonry structures. In future we may be able to reduce the cement by weight to about 1% of the lean concrete by weight.

- the insulation is not foam. It is rigid expanded polystyrene (EPS/ Styrofam) and is completely encased in lean concrete of a minimum of 2 inches cover.


sultanj




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creator

continuation of response from prior:

- How training of builders compare with other options: The other low emission options, in our case study of Lesotho, do not incorporate insulation. Homes and commercial buildings are not insulated in Lesotho or in South Africa - especially as far as homes of the poor and middle income (majority) are concerned. A lot of the heating is wasted to the environment - because of none or very poor insulation. In order for homes to leverage the thermal mass, preventing heat loss is essential. In order to stay cool in summer - insulation is essential. Our structure type provide that. The need to train people is also to give them a skill set so they can be employed in the commercial sector and for building homes for the middle income and richer folks. Lesotho does not have a manufacturing economy so construction provides a rare opportunity for employment. This is true for lot of countries in the world. If people have jobs, they will have money, and they can build their homes using the skill they have learnt, with sweat equity participation, collaboration among family members and neighbors - and by renting the reusable forms. The reusable forms are key to reducing cost, and developing a regime of shared resources. The forms pay for themselves after 4 homes or so. A lot of vendors can be encouraged to make these forms and rent hem for two to three week periods - needed for construction of a small home ( one bedroom, toilet and Kitchen).

- we think this system will work for poor countries. There are challenges but they can be overcome in time and proper planning/ management. The key to the technology is in the re-usable form. The challenge is not in the form itself, but placing the form with in-expensive connectors and quickly releasing the form after the concrete pour. By learning how to stack them vertically and safely. We have worked extensively on this issue and we now have a system that is cheap, quick and produces quality vertical walls - as evidenced in our work in Lesotho and also a building we completed in New Orleans last year, using similar forms, connectors, and concrete pour using boom trucks etc. - with huge pour load and velocity. The forms also allow us to change the width of the wall - in case we need to have thicker walls with higher insulation value (sun/ heat orientation factor)  etc. Such flexibility is not easy in dimensional masonry blocks. Our forms work and we are optimistic.

- Yes the homes are very comfortable. The poor have limited resources, they are contributing to global warming with their fossil fuel heated homes, and if we can provide a less expensive option for their shelter - that is a desirable outcome.


sultanj




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Proposal
creator

clarification of our prior comment:

- please note the comparison of masonry wall to our structure type, in our prior comment, only compares use of cement in the wall systems. It does not include use of cement for beams, columns, footing which we believe will be comparable for both masonry construction as well our proposed insulated, poured in-situ system. Their is certain amount of vertical and horizontal steel required by building codes for masonry construction and also in columns and beams and we believe the quantities needed would be comparable to our system. 


sultanj




Member


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Proposal
creator

In order to clarify some of the questions raised by the judges, we have modified and edited our write-up, as well as added graphs and charts, to the section titled " What action do you propose ?"