Flat Pack House: Low Energy Style O

Low energy house O

Published July 16th 2009. Updated 16th January 2011.

The concept: Is a flat pack style home. A 3mx3m modular layout, designed so the occupant can decide their own floor plan from 18m2 up to what ever m2 in a flat pack kit. Quantities for the chosen house type would be arranged and supplied from the warehouse and delivered in a simple kit, erected quickly and made water tight in a week ready for the chosen fixtures and fittings to complete the build.

I have currently produced two floor plans just as an example of what’s possible with the design. The illustrated project below is the first to come off the drawing board. The second was developed specifically for a narrow piece of land and on a tight budget. Due to strict planning restrictions with the low energy house at Martinsberg we were not free to run away with the design. It had to have a red-pitched roof, blend in with the surrounding, no more than 20% solar panels to the roof and restricted to a 50m2 floor plan. The new plans move away from the traditional three bedroom house style and offers the public an alternative  ”house” with minimal yearly running costs. I can only vouch for the the houses proposed performance figures here in Tubingen where summers reach +30 and winters can dip to -20,  so not the easiest of climate conditions to design for.

The Architecture: Simple and Minimal

The design is made-up of three squares encasing one another growing in size by the golden ratio.

The outer shell provides the shade and protects the main house from the harsh elements by means of 5m high rolling vertical Larch shutters that can be fully opened and closed to suit the changing seasons. The middle Square is the living accommodation spread over two floors, the inner square creates a protective calm and quiet courtyard helping to stabilize temperatures to the middle square and offering a semi-exposed area from the elements.

The Interior

The floor plan you will notice is nothing new. It’s a floor plan that has been used time and time again through history. I don’t particularly “do” standard internal walls and doors so the centre courtyard design naturally gave me that room-dividing feel I wanted without using traditional methods, but really the main reason for the courtyard is a ventilating advantage to the design. It not only helps the external winds to be easily pulled across the whole internal space but it also provides a cooling oasis in the summer for the building to be able to breath and for the occupants to be able to retire somewhere constantly cool. In the winter the house is designed so the low-lying sun can penetrate directly through the inner courtyard and providing an encased sheltered sunny winter garden behind glass.

The landscaping

It’s still on the drawing board. Well it is nearly finished; just don’t want to up load it. One major change I have done from what appeared in the Martinsberg project is to ditch the submersible log burning wooden hot tub for a more minimal Ofuro Japanese bath on the west terrace. Working on the details now of getting hot water from the solar tank to supply the Ofuro and external shower but its all just technical details to work out. Just need to transfer the garden-planting scheme over onto the computer as it’s all still in hand drawings.

The Model

With the aid of the model I tested a wide array of potential ideas. As shown on the next pages the 170m2 version was designed to be around a centrepiece silver birch courtyard, not just for design purposes but an important role in the concepts passive design. The model was more useful than just visually seeing the project in a three dimensional proposal. It helped pick out concept errors, the movement of natural light around the building, general internal aesthetics, scales and proportions with the golden ratio, modular timber sizing, flat pack research and material quantities.

As shown in the photos I firstly prepared a cut list for the modular framework so I could assess material lengths and estimate transport quantities.

I use http://www.gaisma.com for sun plotting data. The model will represent these figures in real life showing the extent of the suns ability to penetrate deep into the concept during the winter months as well as displaying true shadow lines achieved so can we estimate the extent of the concepts summer shutter design.

Technical details

The next step on from living in a low energy house was to collect the18 months of recorded data and see what we could do to improve the performance figures. Better figures can easily be reached but at what extra cost. Unlike the first project the Orient Chapple is designed to be located on a flatter plot. Land price will increase but access, excavation, engineering, foundation design and split level wall construction costs will drop in price.

New topics I’m currently researching for the project include: Solar chimney, cooling centre stack, earth ramming, earth tubing, green roofs, solar tanks to tank-less water heater systems and under floor heating.

The tried and tested products already used on the low energy house will obviously be incorporated into the proposed technical brief.

Extensive (Sedum Carpet) Green Roof.

Due to the immense temperature gains with flat roofs we increased the existing 14cm high performing insulation by 2cm to help stabilise thermal time lapsing. We would split the roof design between a green roof style over the main house and sheet metal cladding to the concepts over hangs. This would reduce problems of over heating in summer to the main roof and still having a large enough surface area of roof to collect non-contaminated rainwater for the concepts rainwater harvesting storage requirements.

Passive south elevation

As the low energy house, Martinsberg had restrictions to the floor plan size it was not feasible to create a second layer glass wall. For this project Tri- fold doors will be located to create that needed summer heat / winter sink buffer passive design requires. It means the new house will take full use of passive design. This in return will account for the biggest saving for artificial heating/cooling to the concept idea.

Insulation

Push the roof and walls by 2cm with high performance insulation. I’m going to push up the North elevations insulation internally by 8cm mineral batt style to improve the acoustic value and to in-case the projects pipe work.

Suspended ground floor

Increasing the floors thermal mass by means of high performing insulation rather than standard stone wool between the joists and also upping the load-bearing insulation above the joist.

The heating system

I’ve been working out on what it seems like forever to configure the most cost effective way to heat and supply the new house plan.

So here’s the proposed system.

The same log burner will be incorporated into the design offering a centerpiece fireplace to the room while contributing its hot water along to the 900ltr solar tank. Increasing the hot-water solar system to accommodate 6 adults  so will increase the roofs solar heating panels up to 12m2, but how to heat the rest of the house? Under floor heating (wet system) supplied from the solar tank to three ground floor zones. Will work the same frame structure idea so the warm air is not trapped under the first floor but allows the heat flow up and through the building so no UFH to the first floor. My problem was, what happens if the system is over loaded in the winter and takes all the heat generated in the tank and starving the domestic hot water supply. A few years ago I researched into tank-less hot water systems that use a tiny amount of electric to heat water. As you know all the energy in heating water is from 0 – 9 Degrees. Heating water up from this figure uses very little electric. The proposed system will run its domestic hot water requirement firstly through the solar tank then run through the tank-less water heater achieving a constant supply of hot water. This means it will always have a chance to be pre-heated before going through the tank-less system. This will take the pressure of the solar tank leaving the bulk of the hot water for the under floor heating.

The final stage will be to add a 1.8kw Photovoltaic solar system on the green roof so to balance out the energy demands in winter, electric back to grid method. It would mean the energy used through the winter would balance out from the electric generated in the summer for the tank-less hot water running cost.

The photovoltaic system should equal out the electric demands used per annum but further research needs to be assessed to achieve realistic figures.

 

 

 

Concept For a Green Community: The Design

Concept for a green community:

Top obligation for the green community project would firstly be to achieve a 100% renewable energy supply. The design itself would drain such a low amount of energy that the produced bulk of its electricity would be transferred to the national grid, giving the advantages of supplying more energy than it requires and so offering the community with its own private 15 year investment plan. Working firstly with “passive design” we can reduce the sites energy desires at the conception stage and forecast accurately calculate energy required vs. the energy produced.

Passive design: To achieve this objective I worked with a mixture of earth rammed structural walls combined with light laminated timber frame beams tied into a two layer summer/winter buffer compartmented glazed area shaded by a thin vertical larch open able facade to the lake view.

Backbone of the design: Rammed earth structures utilize locally available materials. Setting up an earth mover to the centre of the lake would supply the material for a giant in situ earth rammed curved wall constructed to the outer ring of the project, minimal to the environmental impact and generating very little waste. The materials mass allows the building to “breathe”, avoiding condensation issues without significant heat loss and offering stunning “time lapse” performance figures from the materials natural make-up.

Roof design: 70% Extensive Sedum carpet green roof systems: Ecological alternative to large conventional surfaces so contributing to lowering the summer radiant heat temperature to the local site. 30% Metal finish to the insulated garage roof tops merge into the green roofs so offering an area of non-soil contaminated rainwater supply for the rain harvesting system.

The site: By means of an in-depth site study we can precisely arrange the site to take full advantage of the solar calendar, which would include collecting data with regards to solar radiation, solar orientation, local wind directions, monthly temperatures and so on.  From this collected data we manipulate the usage of the yearly seasons to our advantage. A ring of deciduous trees would encase the project but only by carefully planning. The planting scheme would help shade the site only where needed but not to interfere with the sites air -flow and shadowing of the solar farm. Grass paving system to the parking outer ring pass ways, solar farm zone, community hall’s exterior, site slopes and banks. Clay inter locking blocks to the main outer ring service road fitted with storm water drains complete with oil catch filters and channel piping directed to the grey water reed bed irrigation zone.

Artificial lake: Shallow to edging 1m – 5m at the deepest part of trench. Gentle run off created to beach area. Naturally landscaped edge. Aquatic plant management plans for stabilising the lakes ecosystem yet still offering areas for swimming, boating and fishing to segregated areas.

Low energy house, Germany

Low energy house, Martinsberg

Location: Tubingen, Germany. 48º 27’N, 8º 57’E.

Architecture: Nick Chapple. Interior designers: Nick Chapple, Sharonah Luderitz. Project Manager: Sharonah Luderitz

Structural Engineer: Hans Ulrich Strobel. Construction: Joseph Kessler, Nick Chapple. Landscape: Helmut Hoesch, Nick Chapple

The idea was to develop a low energy, low cost housing modular, designed to be easily adaptable to different orientation of a site and versatile enough to being used in a small housing development. We worked on a realistic and cost effective approach rather than cramming every possible green addition to a building by means of Eco-Bling. By carefully balancing price verses performance we gained an eco-minimal design.

Summary of areas covered

Passive design tendencies, natural ventilation, solar hot water systems, rainwater harvesting, landscaping and site orientation, material studies, health in design, Impact to the environment and designing with natural light

Technical issues

Designing the buildings envelope, cost effective heating requirements, estimating project running costs, dividing up power requirements and simple structure design. It’s not all about solving technical problems but about the role of the details as essentially defining the whole. An innovative detail can alter the perception of a whole design and simultaneously reflect an entire design concept by itself. The design hopefully comes across very simple in design and architecturally soothing to the environment. We needed to achieve an energy conscious building form taking climate concerns into consideration and responding to the microclimatic particularities. A carefully thought-out design adapting a build to the natural energy potential in order to utilize it efficiently was the task. Japanese influence for innovative design solutions. Radically implement small spaces, nowhere else are structures pared down so rigorously to the barest of essentials. The simple modular construction was prepared in the workshop dramatically reduced the build time and saved valuable labour costs onsite.

Japan has traditionally demonstrated great openness to influences from the outside. We worked on the boundary between indoors and outdoors to be dissolved so the terrace, stonewalls and landscape merged within the Internal space. Split between these open boundaries is the location of the bathroom doubling its size when opened to the elements and offering a calming water play to both areas. A Scandinavian designed wooden hot tub becomes focal point to the laid back top terrace area. The bathrooms south elevation allows winter sun light to penetrate deep into the Interior pulling light across the whole project surface by means of glass walls. Even though the compact 1.2 sq m technical room is located centre to the houses layout it appears to dissolve behind opaque glass and becomes a lit up cube.

A 8m solar collector supplies the 600ltr solar tank making sure it can sufficiently run its daily hot water demands for 4 people through out the warmer months. From October to March the design works on solar gain from the south elevation and the projects wood burner with a 7kw back burner pumping its contributing hot water to the solar-tank. The house is designed for the centrally located burner to move its warm air freely around the whole interior without any internal restrictions.

Natural ventilation and airflow design to the project was assessed after collecting information on microclimatic weather patterns and general wind directions. The general local trade winds blow from the west in summer, from this high and low window openings were created to effectively draw in the outside cool air over the warm interior surfaces. The design has no obstructive internal objects so allowing clear passage ways for the air to be pulled out through the east elevation openings creating a continuous cycle of air to flow through the building.