This study aimed to evaluate impacts of ventilation designs on indoor airborne transmission for mixing ventilation (MV) focusing on ventilation effectivness. Different flow rates (8 to 40 l/s), exhaust positions (high and low), source locations and effects of air cleaning were tested, and particle concentrations with different size fractions were measured. The results showed that the ventilation effectiveness was decreased with an increased flow rate, which was reduced from about 1.15 (with 8 l/s) to 0.9 (with 40 l/s) for a standard MV configuration. With 30 l/s the effectiveness was about 1. This trend was due to stratification with low flow rates and short-circuit related to high flow rates. Although lower flow rates showed greater ventilation effectivness at the compared locations, higher flow rates would always provide better dilution. This suggested that a balance between the contaminant dilution and removal should be considered when increasing flow rates to enable sufficient and effective ventilation. Moving the exhaust from the ceiling to floor level was less effective due to short-circuit. Placing the source close to, and under the exhaust helped to remove contaminants more efficiently. Air cleaning added significant impacts on ventilation to reduce particles for the supply flow rate of 15 l/s

Single family houses with balanced ventilation have become more airtight, heat recovery efficiency has increased, and rotary heat exchangers have become the most common. All these changes combined increase the risk of moisture convection damage when it is very cold outside. However, theoretical studies have shown that it is possible to control airflows and rotor speed, in such a way that the risk of moisture damage is minimized. In collaboration with the ventilation industry, this project has developed a dynamic method of testing, in a controlled laboratory environment, how air handling units control systems can handle realistic variations of internal moisture generation in a moisture-proof way. The methodology means that an air handling unit with its control system is connected to a hardware-in-the -loop test facility that can in real time simulate an installation corresponding to a real house with different outdoor temperatures and internal moisture generation. The output from the test is how the moisture content varies in different rooms, extract air and supply air, as well as the variation of supply and extract air flow rates. Ventilation with different control strategies have been tested. In the project it has also been studied how the moisture recovery in rotary heat exchangers with different moisture-recovering properties varies depending on rotational speed, airflow, and outdoor temperature. It has then also been possible to verify previous theoretical calculations. The main conclusion is that by controlling the rotor speed and the air flows, the moisture contents in the indoor air can be controlled during periods of high moisture load

This paper characterised the potential of energy flexibility in relation to building envelop properties, heat emitters and ventilation for the Swedish context. Simulation results indicated that the potential was higher for newer houses with floor heating and lower for older houses with radiators in winter. Older houses with different levels of insulation showed a similar ability of conserving heat due to different extents of heat losses from ventilation. A house with balanced ventilation tended to be over-ventilated especially if the house was not airtight. The flexibility was decreased with increasing outdoor temperatures, and it was higher in winter and lower in spring/autumn. 

I denna studie har energiprestandan för 11 olika småhus bestämt dels genom beräkning med två olika energiberäkningsprogram, dels genom att samma hus har energi-deklarerats av en oberoende energiexpert och slutligen har energiprestandan bestämts genom en stegvis normalisering av uppmätta värden enligt anvisningar i Boverkets förordning BEN. Jämförelse har gjorts mot nuvarande energikrav och de energikrav som gällde när byggnaderna uppfördes. Jämförelse har också gjorts med de i projekteringsskedet genomförda energiberäkningarna.

De 11 husen valdes ut i samråd med fyra olika hustillverkare som har bistått med underlag i form av ritningar och beräkningsunderlag. Husen har en geografisk spridning från Skåne till Norrland och har olika installationstekniska lösningar. Samtliga hus har besökts och dokumenterat på plats.

Samtliga hus bedöms uppfyller de energikrav som gällde när de uppfördes men några har svårt att klara de energikrav som gäller i dag. Främst gäller detta fjärrvärmda hus. I genomsnitt ligger beräknade värden lägre än uppmätta och normaliserade värden, framför allt gäller detta jämfört med energideklarationerna. Det bedöms dock att energideklarationerna som är gjorda utifrån en enkät och utan att man besökt husen har en hel del brister, bland annat redovisas i de flesta fall ingen fastighetsenergi vilket flera fall påverkar beräkningen av primärenergitalet på ett felaktigt sätt. Men även den detaljerade normaliseringen är osäker beroende på att tillgängliga mätdata har stora brister. Att flera hus anger användning av ved till braskamin är en bidragande orsak till att beräkningarna hamnat lägre.

Oavsett så rekommenderas att man i energiberäkningar har viss marginal till kravnivån avseende energiprestanda. Detta då det är svårt att vid en normalisering ta hänsyn till alla beteendemässiga avvikelser från det ”normala”, samt att det även finns osäkerheter kring de flesta indata till en energiberäkning såsom U-värden och köldbryggor, lufttäthet, temperaturverkningsgrad med mera.

Med användning av en viss säkerhetsmarginal bedöms en energiberäkning på ett färdigställt småhus kunna vara en väl så säker metod för att bestämma dess energi-prestanda som en normalisering av uppmätta värden.

På grund av de osäkerheter som är behäftade med båda sätten att bestämma energi-prestanda kan man inte förvänta sig att alltid kommer till samma resultat.

Det finns behov av att förbättra Boverkets förordning BEN både när det beräkningar och normalisering av uppmätt energianvändning. Framför allt gäller detta hur man ska hantera el från solceller.

Boverkets remissförslag till ändrade energikrav i BBR2020 innebär att det blir svårare att klara energikraven med frånluftsvärmepumpar, framför allt för mindre enplans småhus. Däremot blir det avsevärt mycket lättare att klara kraven med fjärrvärme och FTX-ventilation.

In this study, the energy performance of 11 different single-family houses has been determined by calculation using two different energy calculation programs, through energy-declarations made by an independent energy expert and finally trough a stepwise normalization of measured values according to instructions in the regulation BEN published by the National Board of Housing, Building and Planning (Boverket). Comparison has been made with current energy requirements and the energy requirements that applied when the buildings were constructed. Comparison has also been made with the energy calculations performed during the design phase. The 11 houses were selected in consultation with four different house manufacturers who have provided support in the form of drawings and calculation data. The houses have a geographical spread from the north to the south of Sweden and have different heating and ventilation systems. All houses have been visited and documented on site. All houses seem to meet the energy requirements that applied when they were built, but some have difficulty meeting the energy requirements that apply today. This mainly applies to the houses with district heating. On average, calculated values are lower than measured and normalized values, especially when compared to the energy declarations. However, it is assessed that the energy declarations made from a questionnaire and without having visited the houses have a lot of deficiencies, among other things, in most cases no real estate energy is reported, which in several cases affects the calculation of the primary energy incorrectly. But also, the detailed normalization is uncertain because available measurement data have major shortcomings. The fact that several houses indicate the use of wood for wood-burning stoves is a contributing factor to the calculations being lower. Regardless, it is recommended that in an energy calculation, there is always some margin to the requirement level regarding energy performance. This is because during a normalization it is difficult to account for all behavioral deviations from the "normal", and that there are also uncertainties about most inputs to an energy calculation. However, if using proper safety margins, energy calculations on a completed house can be just as good as a normalization of measured data when determining it´s energy performance.

There is a need to further improve Boverket's regulation BEN, both when it comes to calculations and normalization of measured energy consumption. This is especially important regarding how to handle electricity from solar cells.

This paper describes the principles for retrofit design of Near Zero Energy supermarkets, i.e. to minimise the energy use and ensure that the remaining energy needs are met by a supply of renewable energy. Pressure for energy improvement of buildings has increased steadily over the last couple of decades. Several different aspects must be considered in the design of a supermarket - some of which are described in this paper - such as requirements, refrigerated appliances, lighting and other equipment, building technical services systems, building envelope, energy supply, energy storage, life cycle costs and consideration of the needs of those using the building. For a supermarket, special attention must be given to the food, personnel and customers, three categories with differing environmental requirements. Different designs for retrofit energy efficiency improvement installations are compared and suggested for two existing stores: one in a free-standing building, and one in a larger property.

Vi har tidigare sett och verifierat att man idag kan bygga mycket energieffektiva och lufttäta byggnader med lätta konstruktioner i klimatskalet. Byggsektorn har allteftersom också arbetat med utbildning och tekniska lösningar för att bygga lufttäta klimatskal i dessa lätta klimatskal. Med tillämpning av dessa kunskaper, erfarenheter och produkter kan man konstatera att man mycket väl kan producera kvalitetssäkra lågenergihus med lätta klimatskal. Det har dock hittills inte varit lika mycket fokus på byggandet av lågenergihus med andra typer av stomsystem som också har möjlighet att användas för produktion av lågenergibyggnader. Exempel på sådana andra alternativa stomsystem som kan övervägas vid produktion av lågenergibyggnader är massiva klimatskal i betong eller trä. Inom ramen för detta projekt har syftet varit att teoretiskt simulera och genom intervjuer samla erfarenheter från framförallt byggandet av tunga och massiva klimatskal i betong för att kunna utgöra ett beslutsunderlag tillsammans med tidigare erfarenheter från lätta klimatska vid val av stomsystem.