heat exchanger

This paper shows how air-to-air heat and energy system design problems can be formulated for a simple HVAC configuration and solved for the least life-cycle cost system while still retaining a small payback period. Mathematical expressions and design tables are presented to facilitate the design process. The design process is illustrated for the city of Chicago where both large heating and cooling loads occur in HVAC applications. The example design problem presented shows that

Several configurations of air to air ERHXs exist, they include heat recovery ventilators and energy recovery ventilators. They are placed in ventilation units, unitary air conditioners, and air-handling units that take in outdoor air while venting indoor air.
Those air to air energy recovery heat exchangers reduce HVAC energy consumption and reduce the required air-conditioning capacity of the building too.
But a periodic cleaning to maintain effectiveness is necessary. During the heating season in cold climates, a frosting protection may be necessary.

Describes the principle of ground heat exchangers for outside fresh air, giving indications about their design rules and their energy performance, as well as recommendations for their hygienic operation.

Describes the two main systems used for ventilation heat recovery : static air-to-air plate heat exchangers, air to air rotary wheel heat exchangers. Indicates briefly their main characteristics.

The needle heat exchanger (acts as a pre filter EU3) was installed in front of the glass fiber used as a fine filter (EU7) in the supply air chamber. Thus, the temperature of the supply air increased and the relative humidity of the fine filter next to the heating unit decreased. The aim of this study was to examine how the installation of the needle heat exchanger effects on the microbial growth and release in the fine filter. The relative humidity of the fine filter in the supply air unit fell below 70 % during different seasons.

This paper presents an analysis of air-to-air total heat exchangers (heat and mass transfer) built up using moisture permeable paper (but impermeable to air molecules). Performance of 6 such total heat exchangers made of different types of paper were tested, in order to know their air leakage ratio and their energy saving ratio. An analysis is presented about the effect of leakage on energy recovery efficiency.

Following calculations of potential energy savings, several types of earth-air heat exchangers have been coupled to buildings in novel concepts for passive heating and cooling of ventilation air. For the first time this technology was used in the Belgian climate. In a first case one short plastic tube is coupled to the HVAC system of an office building, to preheat/precool the fresh ventilation air. Measurements are presented on this system and it is shown that performance could have been improved by more concern during the design stage.

Earth-air heat exchangers can be used to reduce energy consumption in building ventilation systems. The idea is to pre-heat air in winter and pre-cool air in summer using the thermal capacity of the soil. To do this concrete and plastic tubes are put underground, through which the ventilation air is drawn. In this paper a 3D unstructured finite volume model is derived, which allows evaluating the earth-air heat exchanger. The model solves conduction through the soil and the convection from air to the tube wall.

The paper presents a short description of the measurement program and the data collected for the “SynergieHaus”-project initiated by PreussenElektra and partners (now merged to E.ON). Results of airtightness measurements (ACH 50-values) are shown for a to

A Japanese electronics company has developed a new type of gas-to-gas heat exchanger, called the Ductron. The heat exchanger has a simple structure composed of aluminium or stainless steel pass partition plates stacked with a gas passage (1 cm wide) between each plate, Heat exchange duct- Ductron and can be installed as part of an air duct system. It is applicable not only to HVAC systems but also to various industrial applications. The efficiency level is over 5 0%.