Jørgen Munthe Schultz

WinSim: A simple simulation program for evaluating the influence of windows on heating demand and risk of overheating

A two-node model of a room has been implemented in a computer program, WinSim, developed for evaluation of thermal performance of windows in new buildings and in case of retrofitting. The program calculates the annual heating demand and the number of hours with indoor temperatures higher than a user defined limit. WinSim is characterised by the limited amount of required input data. Guidelines for calculation of the effective thermal capacity of the room are given, and results obtained with WinSim have been compared to results from an advanced building simulation program. Good agreement has been found between the two programs with respect to calculated annual heating demand and energy savings due to window exchange, and also the calculated number of hours with overtemperature is similar. Based on the limited examples used for the comparison, it can be concluded that WinSim is well suited for a quick but realistic evaluation of thermal performance of windows.

Solar Heating Systems With Heat of Fusion Storage With 100% Solar Fraction for Solar Low Energy Builidngs

A storage concept based on the phase change material (PCM) sodium acetate trihydrate and active use of supercooling is theoretically investigated by means of TRNSYS simulations. The supercooling makes it possible to obtain a partly heat loss free storage when the melted salt due to heat loss supercools to the surrounding temperature and no further heat loss occur. The heat of fusion energy is preserved and can be released by activation of the solidification on demand. The investigations show that 100% solar fraction can be reached in a low energy house in a Danish climate with a solar collector area of 36 m2 and a PCM storage volume of 6 m3 combined with a 180 litres DHW tank. Experiments have proved that it is possible to melt large volumes of sodium acetate and an automatic controllable activation mechanism has been developed and tested.

Energy Savings for a Solar Heating System in Practice

In July 2006 A New Developed High Efficient Solar Heating/natural gas heating system was installed in an old one family house in Denmark. The new system was based on 6.75 m2 solar collectors and a condensing natural gas boiler. Before the installation of the solar heating system, the house was heated by a non condensing natural gas boiler.