You have been using HOT2000 to determine if house designs meet the R-2000 energy target and have always believed that it does a good job. One day you decide to model your own home and compare the results to the utility bills. You find that the predicted and measured energy usage differs by a significant amount! Does this sound familiar? What's going on? Why the difference? Does this mean the utility meters are no good (unlikely); that you don't know how to perform take-offs (shudder); or that HOT2000 is no good (shriek)? Don't panic.
As part of a project financed by the National Foundation for Energy Research (NEFF), the Building Services Section at the EMPA examined the thermal behaviour of one building, with zero energy demands, located in a low energy housing estate in Waedenswil on the border of the lake of Zuerich. The estate was initiated by Dr. R. Kriesi who also made the energy concept. The architect was R. Fraefel and the estate was financed also by the government of Zuerich. The measures taken in order to reach a minimal heating demand in the chosen zero energy test house were as following:
A basic condition for low energy houses is a demand controlled ventilation combined with an air-tight building envelope. Within the scope of different research projects financed by public grants and measurements effected by private order mainly in the south of Germany, the airtightness in low energy and minimum energy houses has been checked according to the DC pressurization method and the places of leakage have been determined. Considering the results with respect to the recommendations of the SIA 180 (standard of Switzerland), 40% of approx.
The aim of the study was to design and build a small house with 50% lower heating energy consumption than in typical existing Finnish small houses. Energy saving is based on three technologies: super insulation, airtight construction and ventilation heat recovery. The first monitoring results show the heating energy consumption of the house to be less than half of the measured consumption of typical small houses located in the same area. Also, the results show the air quality to be good.
Intermittent heating patterns, characteristic of Israel and other countries with a mild winter enable energy · conservation at the expense of very high peak energy consumption; · very low levels of thermal comfort; and surface condensation and mould growth problems. The paper summarizes a research project which included analysis of total daily energy consumption, partial energy during evening (peak) hours, weighted cost of total energy, improved thermal comfort, internal surface temperatures -of the external envelope, and surface temperatures of partitions.
The computer model SIN-BIP is built as a combined model that can calculate energy consumption, price and environmental load for a building to get an energy efficient building. The program has a database with information of price, thermal conductivity, moisture conductivity, energy content and CO2-emission for materials. On the basis of this information can the program calculate for each construction, the U-value, the moisture resistance (and if there is condensation), the price, the energy used for producing the material and the environmental load from CO2-emission at the production.
New research shows that replacing low efficiency window air conditioners with high-efficiency units can produce measurable savings and can be cost-effective in homes with high air conditioning electricity consumption.
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