calculation techniques

In typical Chinese commercial kitchens, the large amount of heat and moisture that is generated must be removed. The ventilation and energy consumption rates can be huge. Middle and small scale commercial kitchens in China produce an exhaust airflow rate so large that without a reasonably effective ventilation system, the temperature and contaminant concentrations are far more than acceptable levels. To fulfil all the requirements of indoor air conditioning in an economical manner, a new air distribution pattern called air curtain ventilation (ACV) is presented in this study.

Explicit algebraic equations for calculation of wind and stack driven ventilation were developed by parametrically matching exact solutions to the flow equations for building envelopes. These separate wind and stack effect flow calculation procedures were incorporated in a simple natural ventilation model, AIM-2, with empirical functions for superposition of wind and stack effect and for estimating wind shelter.

The paper presents a method of designing thermal comfort conditions in a room with an UnderFloor Air Distribution system (UFAD). A two-phase algorithm is based on: a steady or unsteady heat and mass transfer theory in the first step of computation and thermal comfort calculation in the second step. This method is implemented as the computer program UFAD_NET.

This report gives a comparison of the calculation methods used in 21 European countries for energy performance of buildings. It comments the differencies and similarities between these national procedures. Different aspects of calculation methods are analysed in details, including the way to calculate heat losses due to ventilation. Comments are given about the way by which calculations procedures are treating or taking into account points such as minimum ventilation rates, intermittent and demand controlled ventilation, air infiltrations, duct tightness, heat recovery, fan power.

To evaluate innovations and efficiency as regards air-conditioning, it is necessary to know for how long and in which conditions the equipment functions, an indication related with the COOLING LOAD and which is their effectiveness - EER - on average (or Seasonal) known as SEER. We extended the concept of SEER to include all sources of electricity consumption, namely the secondary equipment, and we called this extended concept the SYSTEM SEER.

This paper describes the CFD model implemented within a building simulation program (ESP-r). It gives results examples to demonstrate the application potential of the model to calculate local comfort conditions and air quality.

Based on measured wall temperatures made by an infrared camera the flow and temperature fields were computed for an atrium. The nature of this atrium is a large enclosure inside a school building surrounded by halls and classrooms. Within a hybrid ventilation concept the stack effect during the summer time is used to form the main driving force for the night cooling of the classrooms. Time dependant computations were carried out to obtain the flow and temperature fields inside the atrium under various boundary conditions.

The Building Regulations with regard to the energy performance of buildings in the Netherlands is an attempt to a performance oriented requirement in conjunction with a test standard. The test standard in fact means a calculation procedure. The requirements are given in the Dutch Building Decree. This Decree is coupled to the building act. Within the scope of an application for a building permit is has to be proven that the energy use of the building does not reach the maximum allowed energy amount set for that building.

Short analysis of possible retrofitting operations on the building envelope and on the heating system to save energy. An analysis of residential buildings in various parts of Italy has been performed using the Italian national calculation procedures (UNI) for the evaluation of winter energy need. A more detailed analysis in envisaged to extend the data obtained, using more sophisticated codes in order to calculate the annual energy consumption of the building. This would define normalised energy indices to ensure a more energy aware design.

When studying improvements on room by room air conditioning appliances (RAC), it is necessary to know for how long these appliances function and which is their effectiveness - EER - on average (or Seasonal) known as SEER. A method was developed for Europe, taking into account the cycling losses, the fouling losses and the variations due to outside temperature and humidity. Further to this the load was represented by an equivalent number of hours at full load.