The passive house institute has developed several building techniques to suit the central European climate. The passive house concept and laws remain the same around the world, however different details may need to be found to suit the climate and geographic conditions. The first step is to use the passive house process which will determine solutions for each region and climate.Passive houses may appear quite different but the principle which is to reduce investment through energy efficient design remains the same. The overall heat demand for the house is reduced by means of insulation, heat recovery, passive solar gains etc. and this means the house will have very low energy demand for maintaining interior comfort in the heating season. The peak heating should be projected to lower level than 10W/m² which will require careful planning in colder climates. In other regions however other energy sevices such as cooling or dehumidification could be more important than heating. It is important in every design that comfort is at a high level for the occupant.
After assessing the goals of the passive house it a computer based parmetric study of the design to check the results for energy demand, financial investment and healthy indoor climate.
Kevin
ReplyDeleteI was interested to learn the savings that these heat recovery systems can offer with reductions in final energy for space heating of up to 55% for passive houses and 22% for conventional houses. These systems provide a substantial saving if you consider the savings over the lifetime of a building.
To bring the space heating requirements below 15 kWh/(m2a), structural measures alone do not suffice in central Europe. It is only by means of high-efficiency Passive House heat recovery systems that this target can be met. Heat recovery effective ratios of at least 75% are required. Field measurements conducted within CEPHEUS have shown these ratios can be achieved. However, high overall efficiency is only achieved if the rerduction of ventilation heat losses is not at the price of high electric power input. Electricity saving fans and low pressure losses in the system are essential.
I understand your concerns about the accuracy of the survey with regard to the passive window and floor U-values and these might need to be looked at in greater detail.
All in all a very informative read.
John