Improved heat recovery & air conditioning heat pump - Application in a northern hospital

This paper presents the configuration and some experimental performance data for an improved, custom designed heat recovery & air conditioning retrofitting system, developed for a hospital located in a Canadian cold-climate environment. The two-stage heat recovery system includes a conventional glycol heat exchanger and a prototype of a reversible air-to-air heat pump between the exhaust and the fresh air streams.

CEN/STAR Workshop on HVAC appliances : 50 european experts define prenormative research needs

CEN/STAR establishes needs for co-normative and pre-normative research in support to CEN standardization. A workshop took place in CETIAT (France) on 23-24 january 2003, its aim was to provide an overview of the trends of research and future standardization for HVAC appliances and to define the needs for pre-normative or co-normative research and interaction with standardization works.

Heating and cooling with building elements Mit Bauteilen kühlen und heizen

A low energy office building in Frankfurt (Germany) with water heating/cooling from ceilings was submitted to detailed measurements during two years, in the frame of a demonstration project. Results are given showing thermal comfort and energy consumption data.

The ABCs of DOAS (Dedicated Outdoor Air Systems)

Up to now, the use of a single HVAC unit to handle ventilation along with mechanical cooling was the aim of designers : it permitted to curb the cost of a building's mechanical system. In this article the author suggests a new design approach to treat the ventilation air and to manage the latent cooling load for the building. It consists in "splitting" the building's total cooling load with a DOAS. This approach allows each component of the HVAC system to do what it does best.

Maintenance of HVAC-Systems and components, definition of cleanliness

Maintenance of air-conditioning systems is acknowledged as an important means to run HVAC-systems properly. Although several maintenance programs and standards exist, not many systems are maintained in a proper way. Most standards and programs are not concerned with the indoor environment, they are only concerned with repair and failure-response of system components. Just now, some new guidelines come out in Europe, which contains first definition of cleanliness.

Improved duct sealing

In air-based systems, ducts deliver heat and cool air to conditioned spaces. Taking extra time to properly seal ducts during the installation along with repairing and patching leaks in HVAC duct systems will save cooling, heating and fan energy. With aerosol-sealing technology higher performance ducts in new and existing buildings potentially exist.

Failing grade for most schools. Report card on humidity control

This paper is a report on humidity control in schools mainly located in hot and humid climates : according to the US Department of Energy's investigation, most of them, use packaged cooling equipments that are not able to manage space humidity effectively when delivering a high percentage of outdoor air. Those schools don't respect the requirements of the ANSI/ASHRAE standard 62-1999.
By using the dedicated outdoor system (DOAS) approach, ventilation effectiveness and humidity control can be improved and meet the recommendations of the ASHRAE 62-1999 standard.

Cold beams : comfort within reach of a breath of air

The article describes the different types of cold beams used to cool rooms from cold water. Passive cold beams mainly exchange through radiation and natural convection ; they include no fresh air introduction. Active cold beams are mainly based on forced convection, hot air from the room being induced by fresh air. Mix systems try to combine radiation and forced convection. Main characteristics and advantages of cold beams as well as system design rules are also briefly given.

Displacement ventilation environments with chilled ceilings: thermal comfort design within the context of the BS EN ISO7730 versus adaptive debate

The current design standard BS EN ISO 7730 is based upon the work of Fanger dated 1995, dealing with a steady-state human heat balance model that leads to a prediction of the sensation of human thermal comfort for a given set of thermal conditions. That model was then developed for "conventional" environments. But is the current standard still applicable to more sophisticated environments such as offices with chilled ceiling, in combination with displacement ventilation ? This paper presents findings from a study that sought to answer that question.

Introduction to the concept of exergy

This report describes the characteristics of a thermodynamic concept, exergy, in association with building heating and cooling systems. It introduces the various forms of exergy and the mathematical formulations used to evaluate them. It gives an example of exergy calculation for space heating systems.