Faces (forecasts of air-conditioning system’s energy, environmental, and economical performance by simulation)

FACES is a simulation tool for selecting an appropriate heat source system in the early building design stage. Heat source systems have to be studied at an early design stage, because they are closely related to the floor plan. However, in an early design stage, most  of the problems are unsolved, so that there is insufficient data for system simulations. In order to enable detailed and accurate studies for various kinds of buildings and heat source systems,  FACES utilizes full-scale programs for heat load calculation and system simulations.

Energy analysis of ventilated roof with extended top in hot regions

An extended top of the roof can induce the upflowing wind which flows close to the wall and in this way it increases the intake airflow rate in the air gap. A model was set up to save energy with the consideration of a suitable thickness of the air gap and a suitable length of the extended top. The Computational Fluid Dynamics (CFD) was employed to simulate the wind field in the ventilated roofs with extended top and the cases were carried out according to Changsha’s climate parameters in China. The results show that the extended ventilated roof works very well in summer.

Energy saving analysis of pressure difference control of frequency conversion variable water flow system

This paper discusses the energy saving principle of frequency conversion chilled water system. Analyzes the energy saving failure reason in actual engineering from the pipe lines and the pump two aspects and gets out the reason is adopting the constant pressure difference control method. Through a simplified chilled water system, compares the pump energy saving efficiencies under constant and variable pressure difference control methods. Get out that the frequency conversion system can reach the maximum energy saving efficiency under variable pressure difference control method.

Optimization of the operation of an air-conditioning system by means of a distributed control system

A control scheme for an air conditioning system is proposed, based on the continuous monitoring of the thermal, electric and climate variables. The dynamic behavior of the relevant variables is determined and expressed in terms of a compact model (the system transfer function). In this study, the indoor temperature control loop has been implemented using a conventional PI algorithm. The controller varies the speed of the compressor motor by means of a frequency inverter, which, in its turn, controls the refrigeration load.

CFD simulation of a novel ventilation system of subway station in Harbin

According to the cold climate in winter, a new novel ventilation system was put forward based on the analysis of the heat distribution at the subway station in Harbin. There was no special heating system in winter for subway station with such a ventilation system. In this paper, three dimensional model of the subway station was built, a mathematical model of the novel ventilation system was developed based on the k-ε standard turbulence model, and computational fluid dynamics (CFD) simulations for the ventilation system were performed to clarify the conditions of the temperature fields.

Development of approach to optimization of building envelope design in aspect of thermal comfort and energy use

This study examined the effect of building envelope on thermal comfort. The effects of key energy conservation measures, such as window/wall ratio, transmittance of fenestration glass and shading devices, were studied. The output from EnergyPlus was use to predict their influence on thermal comfort. Standard energy conserving measures proposed by ENVLOAD to reduce indoor thermal discomfort and cooling energy consumption were examined.

Effect of natural ventilation and wind direction on the thermal performance of a building ceiling

Natural ventilation is rapidly becoming a significant part in the design strategy of buildings in situations where electricity is scare or non-existent and saving energy becomes highly important. The aim of present work is to reduce the ceiling temperature by natural ventilation through different opening locations (one window in the front façade and the other window in the rear wall) with sill height ratio of 0.27, 0.36, 0.45, 0.54, and 0.63.

Nearly zero energy hotels the European project NEZEH

The European Union (EU) aims to a 20% reduction of the Europe's annual primary energy consumption by 2020. Furthermore, EU commits to reduce GHG emissions to 80-95% below 1990 levels by 2050. One of the main issues of the EU energy strategy is the radical improvement of the energy performance of new as well as existing buildings.  

Development of self-cleaning top-coat for cool roof

Our recent study has shown that the acrylic silicon polymer is useful to formulate self-cleaning topcoat which may maintain the thermal insulation effect of cool roof effectively. 
A 2K self-cleaning topcoat was formulated with a water-borne type acrylic silicon polymer. Its effect to maintain high solar reflectance was confirmed by outdoor exposure test in comparison with coatings having no self-cleaning function. The solar reflectance performance was well maintained regardless of installation angle, lightness of colour or pigment type. 

High efficiency retrofit in historic buildings by demand-controlled ventilation

Effective conservation of historic buildings subject to monumental restrictions is realized through a re-use for modern functions. In fact an attended and therefore ventilated and climatized building can be maintained in thermo-hygrometric conditions suitable controlled in order to avoid the occurrence of mold. Often only the use can justify a timely and adequate maintenance. Although the sustainability of the requalification requires acceptable management costs and therefore a limitation of the energy consumptions which must be comparable with those today prescribed for new buildings.