IBPSA2007

In order to solve the unbalance problem and increase the system efficiency of central heating, a new-style adjusting model in the building internal system —onoff valve adjusting system which is composed of by the on-off valve 、controller、 indoor temperature sensor is put forward.

This paper discuss about characteristics and energy performance of personal air-conditioning system for a general multi-bed patient’s room. Two types of personal air-conditioning systems are evaluated by the laboratory experiment. Energy performance of a peri-counter FCU (a conventional) air-conditioning system is simulated by CFD to compare with that of personal systems. Compared with the conventional system, personal air-conditioning system has an advantage from the viewpoint of amenity improvement, but may consume more energy for cooling in the system.

A methodology for optimizing the operation of heating/cooling plants with multi-heat source equipments is proposed. The methodology decides the optimal combination of the running of multiple heat source equipments to minimize the energy consumption of a heating/cooling plant. The optimal running combination is decided automatically using MATLAB® Stateflow® tool corresponding to cooling and heating loads. The energy consumption at different running combination is simulated using MATLAB® Simulink® tool. A case study is introduced to demonstrate the methodology.

Natural ventilation is generally accepted as the preferred ventilation option as it is a healthy and energy-efficient means of supplying fresh air to a building. In the USA it is seldom being applied as most climate zones are considered unsuited to apply natural ventilation, mostly due to perceived uncontrollability and very humid and hot or very cold seasons. For mid and high rise apartment buildings the option of natural ventilation is virtually disregarded because the tradition of full air conditioning is so well established.

Energy recovery ventilator (ERV) is generally installed in an air-conditioning system to recycle the cooling load of exhaust air. However, air conditioning systems with the single ERV can not meet with outdoor air load and indoor cooling load in summer, which will cause fluctuation of indoor temperature. The goal of this study is to analyze such a fuctuating scenario of the indoor temperature. CFD and subjective evaluation are used in this study.

The principle of the thermal storage in building mass (TSBM) is storing thermal energy in building thermal mass, such as concrete slab, at night and discharging thermal energy naturally in daytime. It is expected that the thermal storage will be effective for reducing the heating load at the beginning of the operation in a cold region. Adding to that, the indoor thermal environment will improve because it heats up the cold floor slab directly. The simulation model was constituted to recreate features of TSBM, which were observed in a field survey in an office building.

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.

In this paper, three-dimensional air flow distributions in a typical island platform under both natural and mechanical ventilation operation modes were simulated for the whole process of the train entering, staying in and departing from the platform. The mechanical ventilation modes include over-platform supply/under-platform exhaust (OSUE) and overplatform supply/over- platform exhaust (OSOE). Based on the data obtained from the simulations, the effects of natural and mechanical ventilation system on platform air distribution were analyzed.

The indoor climate system, which serves a building with a proper indoor air quality and thermal comfort, has been predominantly designed based on the initial cost. A life cycle approach could improve both the economic and environmental performance. For example, the energy use could decrease. There has been a lack of knowledge, models and simulation tools for determining the life cycle cost (LCC) for an indoor climate system. The objective of this paper is to present a model for calculating the LCC for indoor climate systems. Focus is on indoor climate systems for premises and dwellings.

District Energy Systems (DES), e.g. District Cooling Systems (DCS) and District Heating Systems (DHS), have been widely applied in large institutions in the United States, such as universities, government facilities, commercial districts, airports etc. The hydraulic system of a large DES can be very complicated. They often stem from an original design that has had extensive additions and deletions over time. Expanding or retrofitting such a system involves large capital investment. Consideration of future expansion is often required.