Latest projects & news
- Wolf partner with Genersys Solar
- Passive House in Newbridge (video on Homepage)
- Vphase: Sunday Times & featured on DIY:SOS
- Energy efficiency ratings to be compulsory for home sales
- CNN meets Hans Eek & reports on PassivHaus retrofits
- Hans Eek - The Vision & the Visionary of the Passive House Concept
1. Passive Houses
3. Solar hot water
1. FAQs on Passive Houses
- What is the difference between a Low-Energy House and a Passive House?
This is a bit unfair. It is like comparing a VW Golf to a Bentley.
Both are excellent cars and very reliable! However, there is no comparison. A Passive House will give the occupier an ideal living environment and an energy-efficient building, with exceptional savings as proven by the continuous evaluation by the Passiv Haus Institute in Darmstadt.
When assessing against the Code for Sustainable Homes, a Low Energy house is about a code level 3 or 4, while a Passive House is deemed as code level 6 (the highest rating). True energy efficiency homes which are zero carbon and eco friendly.
- Are Passive houses terribly expensive?
The projects carried out to date have shown that the construction cost for passive houses is not significantly greater than for conventional houses. The additional costs generated by passive houses, such as more insulation, improved doors and heat recovery, are partly offset by the fact that there is no need to install a radiator system.
Construction using passive house technology is a relatively new concept for most contractors, so more time and resources have been spent on training for and planning the first passive house projects. Once the houses are being built, it is extremely important that they are thoroughly sealed and moisture-proofed. This means that the construction workers need more time to complete the project, but this also serves as a form of quality assurance.
Typically, the additional cost may be a couple of percent, which, at once or within a reasonable space of time, is paid back through extremely low energy bills. Once the construction of passive houses is more widespread, the cost will fall even further.
- Is it essential to change to new, expensive household appliances?
Today, class A white goods are widely stocked by most suppliers. They are very good, but do not cost an awful lot more.
- We have heard that it takes a very long time to build a passive house
Right now, when passive houses are a concept new to most contractors, planning and construction may take a little longer. Experience shows, however, that those involved in a number of projects have grasped the technology fairly quickly, and that it does not take substantially longer to build a passive house than a conventional house.
- If the cost of energy will increase, as everyone seems to be expecting it to, what does that mean for those of us living in passive houses?
Living in a passive house is an insurance against rising energy costs, since the energy use in such houses is extremely low. In Sweden, the cost of energy has been increasing for some time. Despite this, we have significantly lower energy prices than countries in Central Europe, where prices are often twice as high. There are clear indicators that Swedish energy prices will be harmonized with those in the rest of Europe.
There are many myths surrounding passive houses. Here we explore some of the myths and how close they are to reality.
- Passive houses must have large south-facing windows and tiny apertures facing north
Whether the windows in the house face north or south is irrelevant to the energy supply. The small amount of solar energy which can be utilised in winter is almost negligible. The important thing about windows is to make maximum use of daylight and avoid unnecessary solar radiation in summer. As a rule of thumb, an area equivalent to 15% of the floor area can be glazed. This figure may be slightly higher if the windows have a lower thermal transmittance, and slightly lower if the thermal transmittance is higher. In the south of Sweden, passive houses can have floor-to-ceiling windows without worrying about downdraughts or radiators below the windows. The architectural opportunities are terrific!
- Passive houses require special architecture
Attractive architecture is a part of the passive house philosophy. There are no contradictions.
- Can any architect design a Passive house?
No, not all architects are fully conversant with the Passive House design concept. Apart from adhering to the design principles, the design elements will need to go through the Passive House Planning Package (PHPP). The software will assess the design against local weather conditions (Scandinavia vs. Channel Islands). Architects need to be familiar with not only the concept of designing a passive house, but also with the latest technologies and products available.
- Can you open windows?
Yes. In summer, opening windows at night will help keep the house cool, though in winter doing so may increase fuel costs for residents as heat will be needed to warm the house back up again.
Unlike air conditioning systems, which can only operate efficiently with closed windows, a ventilation system is not disturbed by the opening of windows. For example, in summer, or when there are lots of guests in the house, feel free to open your windows or patio doors.
- Passive houses are more expensive to build?
Building passive houses costs a few percent more than regular buildings. Passive houses do, however, make for a lower overall cost after only a few years, due to the reduced expenditure on energy. A house has a life of at least fifty years. In this context, the additional cost of construction for a passive house is relatively negligible. How much does a Jacuzzi or a remote-controlled garage door opener cost? Or aluminium wheel trims?
- Passive houses are technically complex
The only apparatus in a passive house is a heat exchanger for ventilation air and the controls on the ventilation unit are far simpler than your television. Filters need to be changed once a year. The fans have a service life of at least twenty years. A good time to change the filter in the heat exchanger is when you are washing the kitchen fan filter, defrosting the freezer.
- Sealed houses suffer from mould
No, the opposite is true. Sealed houses with excellent ventilation are the best way to avoid mould. The warm indoor air always has a higher water content than the outdoor air, as is shown by the fact that our breath condenses when we are outdoors in cold weather. Spectacles mist up when you enter a house. When a house leaks air, water in the form of vapour is also carried by the warm air into the body of the house. Somewhere on the way, it condenses, and this causes a risk of mould. As the air-flow reverses, mould spoors are carried back into the house, where they can cause allergies and illness. The opposite is, in other words, true; the aim should be to create a carefully-sealed house with good ventilation, so that we know where air is entering and exiting when we use it.
- Passive houses are in reality heated by electricity
Just like other houses, passive houses use some of the heat generated indoors. We use a lot of electricity to cook food and keep the milk cold, as well as for lighting, television, computers and to keep appliances on stand-by. Electricity is the purest form of energy. Passive houses have an estimated free power of 4 W per square metre, if you include heat generated by individuals and a certain amount of winter sunshine, and provided that the most efficient appliances and light fittings available on the market are used. Once even more efficient lighting, e.g. LED, becomes available, the level of free energy will fall, for example, to 3 W per square metre.
Energy-efficient equipment, Class A white goods and low-energy light bulbs are recommended.
-Condensation forms on the outside of the windows
Condensation does form on the outside of the windows. Condensation outside is a sign of a high-quality window. Heat radiation into space makes the window surfaces cold and causes them to attract moisture which condenses. In general, this may happen all year round, for a few hours in the morning. This does not happen if the window has a substantial roof edge or sunshade, or is sheltered by trees. With passive houses, there are great ways in which to create both efficient shading against the sun and prevent condensation.
- Will the house be warm enough?
Solar gain, heat from cooking, lighting and computers and the 60-100W of heat everybody emits is normally enough to replenish the tiny thermal losses in a Passive House. A small backup heater is nevertheless necessary for those days in winter when there is hardly any solar gain.
- Does the ventilation system cause bacteria, noise or draughts?
No, cooking odours and dust are extracted with the stale air. Fresh air is brought in and warmed to a constant temperature. The air tight shell eliminates all draughts and the unit is quiet and fits into a standard 600mm kitchen cabinet or under the stairs.
-Passive houses are very demanding of the people living in them
The main advantage of a passive house is the comfort it provides and the great indoor environment, with excellent air quality and no draughts or downdraughts. In addition, it is easy to understand. If you open the windows and create a through-draught, the house becomes cold. The obvious solution is to close the windows.
50% of CO2-discharges emanates from buildings.
Passive houses can both be used in countries with a cold climate and in countries with a hot climate. Heating energy and cooling energy requirements are both reduced (only 10% of the energy is needed for comfort cooling in a passive house, as compared to a traditional building).
As energy costs rise and both the general public and politicians become more aware of the influence of buildings on climate changes, passive houses are being built all over the world. Since there are only financial benefits to be gained from erecting passive houses, the existing market for passive houses will grow rapidly.
The EU is working on a building code which will come into force in 2016, and stipulates passive houses as being the lowest acceptable standard. Great Britain will implement it in 2016 in the form of code level 6 of the Code for Sustainable Homes. Austria has already implemented this as a building standard.
Rapidly growing countries like India and China are working in the same way, to build comfortable, cheap homes which require little energy. It is sometimes cheaper to erect passive houses than conventional ones.
More energy efficient buildings – Market situation
There are currently about 1450 finished, occupied homes in Sweden (april 2010), constructed on passive house lines. The increase in the number of construction projects continues upwards, and a total of around 3000 apartments and detached houses will be completed by the end of 2011.
Passive House Example
Eksjö – single-family house
Ingeborg Eeks house is a beautifully located by the lake at Södra Wixen, near Eksjö. It was built by Stefans Bygg, a local building contractor, and designed by the architect Hans Eek. The frame was constructed using a system of lightweight beams and loose-fill insulation.
The airtightness test showed the house to be more airtight than the passive house requirement. The house is mechanically ventilated with heat recovery. A waterborne heating coil is mounted in the fresh air supply duct. Solar panels and a water-jacketed wood-burning stove provide the house with hot water.
In the first year, energy consumption was 6100 kWh, including the running of the water pump and sewage treatment plant:
- household electricity approx. 2500 kWh
- fans, pumps approx. 500 kWh
- sewage treatment plant, water purification and pump approx. 2100 kWh
- electricity for construction approx. 1000 kWh
Energy consumption is expected to be approx. 5000 kWh/year in the future.
Certified as a passive house, in accordance with the Swedish Passive House Institutes specification of requirements.
Air Handling Unit for Heat Recovery - Rec Indovent Temovex FAQs on Passive Houses
2. FAQs about Vphase
- What is voltage optimisation?
Voltage Optimisation is not a new technology. It has been widely used within industry for years, making huge savings on electricity bills.
Now, with VPhase, this technology is available for use in the home.
- Has this technology been tested?
VPhase has completed its social housing trial with Great Places Housing Group. The data from these trials has been independently analysed and demonstrated average energy savings over the trial period of 8.7%.
Tenants involved in the trials were able to benefit from the immediate and significant money and energy savings the product delivers, without having to change their behaviour or electricity supplier.
There is also an ongoing trial which has been approved by OFGEM for the Government’s CERT (the carbon emissions reduction target) scheme that will determine the lifetime CO2 savings of VPhase and its overall contribution to meeting CO2 reduction targets.
- What does the Vphase unit do?
The VPhase unit is a voltage optimisation device designed for use in homes and small businesses. The unique VPhase product optimises the incoming voltage to a constant 220V giving householders immediate and significant energy savings for the whole home with a single VPhase fitted to the consumer unit (fuse box). Based on our back to back tests, on appliances such as fridges and freezers a VPhase unit can deliver a massive saving of around 17%. VPhase also delivers savings on lighting, washing machines, tumble driers, dishwashers, televisions and a whole range of other electrical appliances.
- Why has this not been done before?
It has! Voltage optimisation schemes have been carried out at major commercial sites for some years in order to save energy and save money.Unfortunately it has not been possible until now to make the technology cost effective for small premises and residential use. We have developed and patented that technology resulting in the introduction of the VPhase unit.
- How does Vphase work?
Across Europe the agreed statutory range for voltage is 207V to 253V. In the UK voltage is typically around 245V. Household appliances must be designed to operate satisfactorily within the European statutory range. Many of the appliances we use regularly will use less energy at lower voltages. VPhase has developed a new innovative and unique smart technology that enables voltage optimisation to be cost effectively introduced into the home. The VPhase unit reduces and stabilises the voltage at the property to a level within statutory limits but below the voltage that is usually supplied by power companies, in the UK the VPhase output is typically 220V.
- Will this work in every house?
Voltage optimisation is appropriate for the majority of properties. For homes with already low voltage supplies you might like to consider reducing the output voltage of VPhase below 220V.
The VX1 reduces voltage to a set level of 220V regardless of how high the mains incoming voltage rises (up to a maximum voltage reduction of approximately 30 volts). If the utility supply voltage falls to 220V or below then the VX1 enters bypass mode and stops reducing voltage. In these conditions the VX1 can not boost voltage so the site simply receives the same level of voltage as provided by the utility supply.
Some commercial voltage optimisation systems reduce the voltage by a set amount (e.g. a fix reduction of say 20V). These systems need to have a site survey undertaken to ensure that they do not reduce voltage at the site to below statutory limits. The VX1 regulates voltage to the set level so there is no need for a site survey. The output is 220V provided the incoming voltage is above 220V.
There is an additional risk with set reduction commercial systems that if the utility company reduces voltage too close to statutory limits, maybe for short periods or transient events, then the site could drop below statutory limits because of the fixed reduction of voltage. This would cause a “Brown Out” at the site. The VX1 does not suffer this problem. If the utility voltage drops below the VX1 set point then the VX1 simply enters bypass mode and the utility voltage is applied to the house.
- Is the Vphase unit the only product available?
The VPhase unit is the first result of the development of our unique technology.
However, we anticipate many other applications in the future.
For instance, the VPhase VX1 is only suitable for single phase installations, which covers virtually all of the households in the UK and some selected commercial properties and businesses. However, other businesses and organisations have three phase electricity supplies - so this represents a potential new range of applications for the VPhase and subsequent product developments.
Currently, the VPhase VX1 is the only domestic voltage optimisation solution available in the UK.
- What size is the Vphase unit?
The unit is about the same size as your existing fuse box and weighs around 4.3kg.
Dimensions of the unit are: 345mm(L) X 180mm(W) X 115mm(D)
- How will it be installed?
The VPhase unit will be installed alongside the consumer unit (fuse box) by a qualified electrician and will regulate voltage to the circuits where energy savings can be made. No on-going monitoring is required to ensure optimum benefits from VPhase. Please check the compatibility of your fuse box with your local qualified electrician.
- Who can install a Vphase unit?
The VPhase unit must be installed by a qualified electrician.
- How can I purchase a Vphase unit?
The VPhase unit is now available! Just give us a call?
- What savings can I expect?
Phase has been shown in independent tests to save around 10% off electricity bills.
In terms of carbon reduction, this equates to around 4 tonnes of CO2 over the 25+ year life of the product. The really good thing is that once it's installed, you don't have to do anything else. You don't have to notify your electricity provider. You don't have to change your lifestyle. The VPhase will silently and unobtrusively make savings; you'll just notice a smaller electricity bill as a result.
- I'm a qualified electrician, what are the steps to installing a Vphase unit?
Simply login and download the installation instructions and technical specifications, as well as Technical FAQs.
- Is there anything I need to do after the unit is installed?
The concept behind the VPhase device is that it's a fit and forget solution. Once installed, there's nothing else you need to do... no change in lifestyle... no need to notify your electricity provider...just start saving instantly!
- Once installed how will I know it is working and saving me money?
That's the really good thing about VPhase - it's a fit and forget product; so, once it's installed you don't need to do anything else to start benefiting from the immediate energy and money savings. The external design is intentionally simple and uncluttered, so, when the green lights are lit on the front of the unit - the VPhase is working as it should be, reducing your electricity usage and saving you money.
We thought about adding an LCD screen displaying your new voltage level, or some wireless adaptor to sync up with your PC or laptop, but to do so would just add more to the cost - and we wanted to make the VPhase VX1 as cost effective as possible.
3. How do Genersys solar panels heat water for your home? (scroll down for FAQs)
Genersys systems are sophisticated engineered thermal systems which deliver heat energy for many different purposes. The most common use is to deliver carbon free hot water for homes, but they can also be used to heat swimming pools, heat space and for industrial processes.
Genersys panels are thermal solar panels. Thermal solar is the use of light to generate energy in the form of heat. It starts with the sun. The sun constantly emits energy by radiation in the form of light. Light can travel through the vacuum of space, but only limited amounts of heat can. When light reaches our planet it is received in two forms. Beam radiation is radiation received from the sun without being scattered by the earth’s atmosphere. Other energy is received in a form that is scattered by the atmosphere and is referred to as diffuse radiation. The scattering occurs when the radiation passes through air molecules, water and vapour droplets and dust. The two forms together are known as total solar radiation.
A simple way to think of these two types of light is to think of beam radiation as the light that you receive directly from the sun and diffuse radiation as the light that exists on a very cloudy day. Each year we get about 4380 hours of light. Only some of this light is in the form of direct sunshine. Genersys panels are designed to work not only in direct sunshine but also in the light levels experienced on a very cloudy day.
The black surface inside the glazed solar panel of a Genersys system is “selectively coated” with a special material made from aluminium oxide. It is called selective coating because the surface is coated in a way that some parts receive marginally more coating than others creating a surface which under a microscope looks like ranges of mountains. This enables many surfaces to be presented to the light.
The reason for the special selective coating is as follows: when light strikes matter in the atmosphere of our planet it causes the molecules of the matter to vibrate. That vibration causes friction and friction is heat. Thus, when you are standing out doors in a cloudy day you can still get badly sunburnt, because the light is causing your skin to burn. The selective coating specially designed and used in Genersys panels enables the molecules to vibrate and create heat in all types of light conditions as well as in below freezing weather conditions.
Once the heat is captured by the solar panels on the absorber plate it conducts into the pipe work running through the panels. This piping is filled with an edible safe glycol to prevent freezing. The glycol is thus heated by light.
The pipe work (which is highly insulated) forms a closed heating pipe which connects to a coil in your domestic hot water cylinder. If you already have a traditional gas central and water heating system, the solar heat circuit will connect to the lower coil in your cylinder and the fossil fuel heating system will connect to the upper coil in the cylinder. You will usually need a new cylinder because solar cylinders are larger than normal cylinders, taking advantage of the ability to store energy in the form of heat for days when there is little light energy available for the solar panels.
The solar heat circuit is pressurised usually to about 4 bar. This enables the solar system to work in very hot conditions (because pressuring the system increasing boiling point significantly) and the glycol enables the system to work even in ten degrees of frost.
Finally in Genersys systems there are sensors in the panels and in the hot water cylinder. These sensors feed information about the state of the system to a digital controller, which is connected to a specially pumping station. When the digital controller recognises that there is energy available in the panels and energy is needed in the cylinder, it switches on the pump; that pushes the hot glycol in the panels around the heat circuit and into the cylinder, making the solar coil in the cylinder very hot. The solar coil conducts its heat to the water stored in the cylinder. When the cylinder reaches a pre-set temperature level the controller switches off the pump and the system returns to rest.
The heat circuit is connected to a pressure vessel to enable the glycol to expand and contract without damaging the system. Some small amount of electricity is used to drive the pump; in typical installations the electrical energy used for the pump and the controller will be less than 1½ % of the energy produced by the solar panels.
It is sometimes thought by a layman that solar collectors are designed to collect as much light as possible and convert it to heat. This is actually not the case. When designing domestic water systems engineers know that there is no point in overheating the system because the hot water usage and storage capacity is finite and the way in which people use hot water and the times at which they use also have to be taken into account. If you make the collectors too hot they will have a very short life time and overheating will cause problems.
At Genersys, we use specially designed and manufactured selective coating, which is designed not to get too hot. There are other coatings that we could use, at lower costs, which get hotter but we have to bear in mind that we are not making collectors to create more heat than can be usefully used because the higher the stagnation temperature and the more frequently the system reaches stagnation temperature, the quicker is the aging process of the whole system. So Genersys panels for domestic hot water are designed so that users never experiences overheating problems and you can safely go on holiday during the hottest times of the year knowing that your system will not overheat and will be safe.
HOW MANY PANELS WILL I NEED?
As a general rule of thumb, one Genersys solar panel will provide enough energy to heat a 100 litre hot water cylinder.
So for example, if your hot water cylinder is 300 litres, an installer would typically recommend you to have 3 Genersys solar panels to provide enough energy for hot water heating.
IT IS NOT VERY SUNNY TODAY. WILL THE GENERSYS SYSTEM WORK?
Although they work best in direct sunlight, very good performance will be given in the indirect light (or diffuse radiation) of a cloudy day.
WILL THE SYSTEM WORK AT NIGHT?
No, the system only works in daylight. At some times of the year there is insufficient daylight and that is why your system has a fossil fuel back up that will cover your needs at these times.
I AM WORRIED ABOUT THE GLYCOL SOLUTION IN THE HEAT TRANSFER PIPE.
Glycol has to be used to prevent the pipe freezing in very cold weather. It is not dangerous – it is a type of antifreeze, but unlike normal anti-freeze it is classified in Europe and the USA as ‘edible’ and is safe for use in food. The Glycol is in a well engineered sealed system and will not leak into the domestic water supply.
SHOULD I CLEAN MY PANELS IF THEY GET DIRTY?
I have noticed some bird droppings or dust or other dirt on the collector glass; shall I wash them off? There is no need to. They will not significantly impair performance and when it next rains they will be washed off.
HOW MUCH CARBON DIOXIDE DOES MY SYSTEM SAVE?
We estimate that your system will save one ton of carbon dioxide a year which is equivalent to about a large sack of soot each year. Over the life of the system each system will save dozens of tons.
SURELY ENERGY WAS USED IN ORDER TO MAKE THE COLLECTORS?
Yes it was but the energy used in manufacturing the system will be recovered after only two years use in this country (less in sunnier hotter countries).
CAN I IMPROVE THE PERFORMANCE BY ADJUSTING THE SOLAR PANEL?
No, it would be very dangerous to attempt to do this. The panel is situated on the roof and there are no user serviceable parts inside. The heat transfer pipe is filled with a glycol solution and reaches a maximum working pressure of 600kPa. The heat transfer pipe reaches temperatures in excess of boiling point so, for example touching it, will cause severe burns. Treat it with the same caution as you would treat a pan of boiling water.
WHAT SHALL I DO IS SOMETHING GOES WRONG.
Turn off the electricity supply to the digital controller and the pump and then call your Installer on the telephone number located in your Logbook, on page 16.
WHAT SERVICING DOES THE SYSTEM NEED?
Very little. Inside keep an eye on the pressure gauge on the pumping station. It should be around 3 to 5 bar. Fluctuations in the course of use are quite normal but if the gauge shows no pressure please contact your installer.
*Every month you should check visually, that nothing has gone wrong outside.
DO GENERSYS SOLAR POWER SYSTEMS CAUSE HARMFUL EMISSIONS?
I have heard that global warming is caused by carbon dioxide and other greenhouse gases. How much of these gases does my Genersys Solar Hot Water System produce?
Your Genersys Solar Hot Water System produces no emissions whatsoever. It is entirely without any discharge of greenhouse gases or other pollution.
WHAT SHOULD I DO IF IT SNOWS?
Nothing. If snow collects on the glass surface of the collector it will rapidly melt. In fact the design is such that it will melt more rapidly from the collector surface than it will melt from other parts of your roof.
WILL THE SYSTEM STILL WORK IN VERY COLD WEATHER?
Yes, the system will work in much colder temperatures than we experience in this country. However, it will not work if the panel is covered in snow as this will prevent light striking the absorber plate. Some of our collectors are fitted to Alpine Hotels where really cold weather is experienced and they work perfectly in conditions of up to minus 30 degrees Celsius.
SHALL I SWITCH OFF THE SOLAR SYSTEM WHEN I GO AWAY ON HOLIDAY?
No - it is better to keep it on.