IBPSA2007

This paper uses two case studies to illustrate the process of building design with due regard to sustainable construction and how the recent changes in legislations affect the way buildings are designed in the UK. Two real case studies cover housing and commercial office sectors. These case studies indicate that a performance based design approach exploiting building simulation offers a building with an improved indoor comfort, lower carbon emissions and added value to the client. Finally, this paper offers some insight into future developments of the UK legislations.

Combined heat, air, moisture and pollutant simulations (CHAMPS) at the building system level are essential for improving energy efficiency and indoor environmental quality. This paper discusses the technical challenges and possible solutions to the problem of coupling an envelope model (CHAMSBES) with a multizone/network model for inter-zonal air and pollutant transport. A representative multizone solver was written, which solves the coupled heat, air, moisture and pollutant transport equations.

Modelling and simulation of energy consumption in Information Technology (IT) building on the Rockhampton campus of Central Queensland University, Australia is presented. Design Builder, commercially available software, was used for the prediction of energy consumption. All the possible sources and uses of energy in building were accounted in the modelling and simulation. The operation of the Heating, Ventilation and Air Conditioning (HVAC) system and the lighting energy consumption of the whole building has been studied in detailed.

This paper presents a model-based supervisory control strategy for online control of building central cooling water systems to enhance their energy efficiency. Simplified chiller and cooling tower models are developed and used to predict the system energy performance, environment quality as well as the system response to the changes of control settings. A novel and simple optimization technique, named as PMES method, is developed and used to seek the optimal control settings under the given working conditions.

The present paper proposes an optimal operational strategy of an actual HVAC system with a seasonal underground thermal storage system using simulation. The simulation is a powerful tool for the system because it is difficult to try various operational methods experimentally in the actual system due to the long heat transfer time in the underground.

A rational method to estimate the energy baseline of a building is indispensable in performing such as retro commissioning, on going commissioning and ESCO (Energy Service Company) projects. Usually a statistical regression method is used to estimate a baseline. But the limitation of this method is that it cannot evaluate the effect of changes in operational conditions such as HVAC system and occupancy schedule, room temperatures, amount of fresh air intake in HVAC systems, weather conditions, etc. by which energy use is affected.

The well-mixing assumptions, uniform distributions of air temperatures and contaminant concentrations and neglect of air momentum effects in a zone, used in multizone airflow network models could cause errors in some cases. Through dimensional analysis of the published data from the literature, this study has found correlation between the errors and mixing levels. Our study concluded that the assumption of uniform air temperatures is not appropriate if the  vertical non-dimensional temperature gradient is higher than 0.03.

Most traditional elementary school classrooms here do not have air-conditioners and it often feel stuffy in classrooms located in the top floors. In addition, traditional classrooms widely have noise problem  so do the open educational classrooms. If the windows and doors are closed to reduce noise, it will result in the phenomenon of stuffiness, which largely prevents the external air entering the room.

It is difficult to investigate the performance of airconditioning systems with thermal energy storage tanks because flow rate in the system is unmeasured in almost all systems. The aim of this research is to estimate the flow rate of such air-conditioning systems using temperature data in tanks which is easy to measure. In this paper, the effects of heat gain through the tank wall, the time interval of data and the number of temperature measuring points in tank on the accuracy of flow rate estimation are studied using generated temperature data by simulation.

The integration of renewable energies in the dwellings is a solution to diminish their energy consumption. It also could represent important money savings for the owner, if the design and the control of the devices are correctly set up. Numerical simulation environments are powerful tools, which help to develop such design and ontrol procedure. The software TRNsys 16 was used to study the entire energy consumption during seven months of the model of a dwelling using thermal collectors and photovoltaic panels.