Termisk analys av kompakta jordvärmesystem - Sensitivitetsanalys och korrektions faktorer baserat på fältmätningar i referensanläggningar i Östergötland
FukttransportJordvärmeSensitivitetsanalysBrinetemperaturDatormodellTechnological sciencesTeknikTechnology and Engineering
Chapter 1 defines the aim of the project and gives a general orientation about ground heat extractors. In chapter 2 physical processes that could be expected to be involved in the heat transport around a ground heat exchanger are discussed. It is shown from a literature study what amount of moisture transport due to thermal gradients there could be expected in a ground heat exchanger. The conclusion is drawn that the moisture gradient (Sr) is of same magnitude as the driving temperature gradient (°C). At the expected amount of increased moisture around the pipes the moisture transport could be considered to have a little effect on the brine temperature. In Chapter 3 and 4 the circumstances are described at the analysed systems respectively the applied methods of measurements. In chapter 5 a computer model named SEBAM2D is described and calibrated. Results from the temperature sensitivity re some environmental conditions are described in chapter 6. The factors that most strongly affect the brine temperature are soil porosity, field capacity, and geographical position. Design factors for the pipe length in the compact systems relatively the system with one pipe/ditch are developed. The factors are presented in chapter 7 and were developed in order to get a medium brine temperature of -3°C during the period 1 December - 1 March. It should be said that the factors are supposed to be used individually and show the relative influence of each environmental factor upon the brine temperature. In chapter 8 some conclusions are presented and discussed. It is observed that the brine temperatures in the compact systems, compared to the one-pipe system, are more sensitive to the environmental conditions. Therefore, it could be expected that the compact systems compared to the one-pipe system are more profitable in soils with good environmental factors. Used data for the computer model is presented in chapter 9 and the literature references the report is based on are given in chapter 10.