AbstractWith increasing population and increasing demands for comfort and thus an increase in energy demand, it is necessary to examine various energy-efficiency measures. This work deals with the ability to control the flow through the heating system to achieve the desired comfort with as little energy as possibleA heating system contains of different parts, roughly speaking, you can divide it to three main components: Heat source, Distribution and Heat emitters. All components are working together to bring heat to the building. What is examined in this report are different ways of adjusting the flow and supply temperature and how it affects comfort and energy use in a building.At today ́s date the conventional method is to use a high flow through the heating system, which affects pressure drop and cooling of the fluid. In the mid 1960 ́s there was an engineer named Östen Sandberg that started to use a lower flow rate with a higher supply temperature as a result. The upside of that was that you could neglect the pressure drop that the fluid in motion contributed with and that it helped to reach the desired comfort.The purpose of this study was to determine if a low flow adjustment is a viable option and to see its advantages or disadvantages.The author of this work has made use of the software IDA ICE 4.0, which is a simulation tool for indoor climate and energy usage, to a build a residential building and then applies different scenarios such as extreme thermal bridges and internal heat. After that used different supply temperature to simulate a low/high flow.A general conclusion of the work when using a simulation of this kind is that a low flow with high supply temperature is better to adapt to different circumstances and is able to keep the desired temperature at the expense of a negligible increase of energy. The adjustment of heating system seems to be an easier task at low flow than at high flow because of the dynamic pressure drop that occurs with fluids in motion becomes negligible.

Uppvärmningen av ett småbostadshus står vanligen för kring hälften av dess energianvändning. Enligt energimyndigheten drar det svenska standardhuset 22,7 MWh per år varav 12,2 MWh går till uppvärmning. Att ge värmesystemet så bra förutsättningar som möjligt bör alltså vara av intresse för varje husägare, kanske främst ur ett ekonomiskt perspektiv men även ur ett ekologiskt perspektiv. I detta arbete har olika energieffektiviseringsåtgärder studerats som kan implementeras i en tvåplansvillas värmesystem bestående av en värmepump, golvvärme på nedervåningen och olika värmedistributionssystem på övervåningen. Åtgärderna har innefattat både praktiska såsom val av isolering i golvvärmesammanhang och mer teoretiska såsom reglerstrategier. Relevant teori för de ingående systemen har presenterats och utgjort grunden för implementeringar av systemen i simuleringsprogrammet IDA Indoor Climate and Energy. Programmet har använts för att simulera en modellbyggnad utrustad med de olika systemlösningarna varvid resultaten sedan jämförts mot varandra. Det mest energieffektiva systemet på övervåningen har visat sig vara lågtempererade radiatorer tack vare kombinationen med golvvärme på nedervåningen vilket tillåter värmepumpen att arbeta med en lägre värmekurva. Även då golvvärme på övervåningen användes erhölls en låg energiförbrukningen, dock på bekostnad av komforten. Elradiatorer, vilka inte kan utnyttja energin som värmepumpen hämtar ur värmekällan, gav den högsta energiförbrukningen. / Heating of a single family residence usually constitutes about half of the total energy consumption. According to Energimyndigheten, the average Swedish house consumes 22,7 MWh whereof 12,2 MWh goes to heating. To bring about as good conditions for the heating system as possible should be of interest for every house owner, maybe mostly out of an economic point of view but also out of an ecologic point of view. This work have studied different efforts aiming towards a more energy efficient system that can be implemented in the heating system of a two story single-family house equipped with a heat pump, floor heating on the first floor and different heat distribution systems on the second floor. The different efforts include both practical such as choice of insulation in relation to floor heating and more theoretical such as control strategies. Relevant theory for the different subsystems has been presented and used for implementation in the simulation software IDA Indoor Climate and Energy. The program was used to simulate a building model equipped with the different heating systems in which the results are compared to each other. The most energy efficient system on the second floor proved to be low temperature radiators due to the combination with the floor heating system on the first floor which allows the heat pump to operate with a lower heating curve. Although floor heating on the second floor also yielded a low energy consumption, it was at the expense of comfort. Electric radiators, which cannot take advantage of the energy the heat pump collects from the heat source, yielded the highest energy consumption.