IBPSA2007

This paper discusses a combination of a dynamic thermal model (HTB2) and a regional energy and emission auditing tool (Energy and environmental prediction model) to analyze the energy efficiency potential of different design strategies, in new or renovated projects. The main aim of the model is to enable decision-makers and other sectors in built environment to predict and account for energy use within a region so that overall strategies and schemes could be made beforehand to reduce energy and carbon dioxide emissions.

Nowadays, the use of translucent or transparent façades as lining of another façade is increasing.

In the framework of the IEA Task 32 (Solar Heating and Cooling Programme), we developed a numeric model to simulate heat transfer in phase change materials (PCM), and experimental data. The analyzed system is bulk PCM plunged in a water tank storage of a solar combisystem (heating and domestic hot water production). The numerical model, based on the enthalpy approach, takes into account hysteresis and subcooling characteristic and also the conduction and the convection in the PCM. This model has been implemented in an existing TRNSYS type of water tank storage.

In present lavatory in Japan, the following are being tried for the purpose of further improvement in the amenity : washable seat, heated seat, deodorization with function stool. In this study, the examination was carried out on the usefulness of the local ventilation system using CFD analysis method on the assumption of the lavatory in office building. In the analysis, it is examined by changing the volumetric exhaust flow rate on ceiling ventilation, local ventilation and ceiling and local ventilation combined use.

Chinese kang, a potentially energy-efficient domestic heating system in China, uses high thermal mass to store surplus heat from the stove during cooking and releases it later for space heating. In this paper a preliminary mathematical model is developed for a House Integrated with an Elevated Kang system (HIEK). This model considers the transient thermal behaviors of building envelope, kang system and indoor air. The macroscopic approach is used to model the thermal and airflow process for the elevated kang system.

Time lags and decrement factors for multi-layer materials without air gaps under air-conditioned and free floating conditions were obtained using the response factor and finite volume methods. The definitions under free floating conditions, which are independent of the external environmental conditions, are proposed for the first time. A special version of the finite volume method was employed in which the surfaces of materials were used as computational nodes and temperatures and heat fluxes on surfaces as primitive (state) variables.

Conduction transfer function (CTF) is widely used to calculate conduction heat transfer in building cooling loads and energy calculations. It can conveniently fit into any loads and energy calculation techniques to perform conduction calculations. There are three methods, Laplace transform (LP) method, state-space (SS) method and frequency-domain regression (FDR) method to calculate CTF coefficients (CTFs). The limitation of the methodology possibly results in imprecise or false CTFs.

This paper explores the simulation of the thermal performance of a radiant floor for heating and cooling that is connected with an underground heat exchanger installed under the concrete floor of a house. In the heating season, an electric boiler is used to maintain the operative temperature at the set point value by varying the supply water temperature to the radiant slab. In the cooling season, the water from the radiant floor is circulated through an underground heat exchanger installed under the concrete slab.