Prospects to Reduce the Use of Energy by 50% in Existing Office Buildings

A comprehensive feasibility study indicates that it is possible to reduce the energy used in Swedish office buildings by 50% within an acceptable economic framework. A recent project managed by an advisory group to The Swedish Energy Agency comprises comprehensive audits, calculations and implementation with the focus to reduce the use of energy in five different office buildings. The average annual use of energy (heat + electricity) before measures is of the order of 200 kWh/m2 and the expected resulting use of energy after measures is on average of the order of 100 kWh/m2 total building area. The required investments to reduce the use of energy by 50% is estimated to be of the order of 100 €/m2 total building area. The paper presents a description of the overall project approach, the studied buildings and the most typical measures, associated investment costs and internal rate of return on the investments

Preliminary Analysis of a Solar Heat Pump System with Seasonal Storage for Heating and Cooling

For higher solar fraction and suitability for both heating and cooling, a solar heat pump system with seasonal storage was studied in this paper. The system scheme and control strategy of a solar heat pump system with seasonal storage for heating and cooling were set up, which is responsible for the space heating and cooling and domestic hot water for a residential block. Through hourly simulation, the performance and the economics of such systems were analyzed, for the different tank volumes, operating modes and weather conditions. The results show that 1) for most areas of China, the solar systems with seasonal storage can save energy; 2) for areas with cold winter and hot summer, it is suitable to store heat from summer to winter and store cold energy from winter to summer, but for chilly areas, it is suitable to only store heat from summer to winter; 3) when the ratio of volume of seasonal storage tank to collector areas is 2~3, the system performance is optimal and the payback period is shortest for most areas of north China; and 4) if cooling storage is needed, the seasonal storage coupled with short-term storage may raise the solar fraction largely

A tutorial on scattering and diffusion coefficients for room acoustic surfaces

There is a need to be able to quantify how sound is reflected from a surface, in terms of how it is spatially dispersed. In recent years, diffusion and scattering coefficients have been developed to enable room acoustic prediction models to be more accurate, and designers to evaluate the worth of diffusing surfaces. Two coefficients have been, or are about to be, enshrined in standards. With two coefficients being standardised, there is great potential for confusion. This paper is intended to bring together authors from different areas to explain where the coefficients should and should not be applied. In addition, this tutorial paper will revisit the rationale behind the coefficients and contrast the coefficient definitions and performance