energy

Rotary heat recovery exchangers are widely used in ventilation systems, and the units are known for their high efficiency and almost maintenance-free operation. Temperature efficiencies above 80% are not uncommon. Performing dynamical analyses of rotary heat exchangers are in many situations advantageous, especially in connection to installation of such equipment in VAV systems. Efficiencies and flows are varying parameters that are crucial for energy calculations, but also for control. The dynamical analysis can effectively be carried out by addressing a dynamical model.

The importance of reducing adventitious infiltration in order to save energy is highlighted by the relevant building standards of many countries.  This operational infiltration is often inferred via the measurement of the air leakage rate at a pressure differential of 50 Pascals.  Some building codes, such as the UK’s Standard Assessment Procedure, assume a simple relationship between the air leakage rate and mean infiltration rate during the heating season, the so-called leakage-infiltration ratio, which is scaled to account for the physical and environmental properties of a dwelling.  The

This paper reports on research carried out to develop natural ventilation control strategies for densely occupied learning spaces with the intention of improving indoor air quality and heating energy consumption. Investigations were carried out for two test cases according to the characteristics given in CIBSE Guide A (2006) and Building Bulletin (BB) 101 (UK Department for Education, 2006). The performance of these test cases were assessed using dynamic thermal simulation with fixed CO2 set-points, based on which opening dampers are controlled.

This document compiles papers produced by staff and collaborators of the Indoor Environment Department at Lawrence Berkeley National Laboratory for presentation at the Indoor Air 2002 Conference, to be held June 30 – July 5, 2002 in Monterey, California. The Indoor Air Conference, held every three years, is the largest international conference on indoor air quality and was last held in the United States during 1981.

A multidisciplinary team of IEQ and energy researchers is working together to define a program of priority energy-related IEQ research. This paper describes the methods employed, ten high priority broad research and development (R&D) goals, and 34 high priority R&D project areas linked to these goals.

Most dwellings in the United States are ventilated primarily through leaks in the building shell (i.e., infiltration) rather than by whole-house mechanical ventilation systems. Consequently, quantification of envelope air-tightness is critical to determining how much energy is being lost through infiltration and how much infiltration is contributing toward ventilation requirements. Envelope air tightness and air leakage can be determined from fan pressurization measurements with a blower door. Tens of thousands of unique fan pressurization measurements have been made of U.S.

Currently, houses do not perform optimally or even as many codes and forecasts predict, largely because they are field assembled and there is no consistent process to identify deficiencies or to correct them. Solving this problem requires field performance evaluations using appropriate and agreed upon procedures in the form of a new process called residential commissioning. The purpose of this project is to develop and document these procedures and to demonstrate the value that applying them could provide in both new and existing California houses.

The role of ventilation in the housing stock is to provide fresh air and to dilute internally-generated pollutants in order to assure adequate indoor air quality. Blower doors are used to measure the air tightness and air leakage of building envelopes. As existing dwellings in the United States are ventilated primarily through leaks in the building shell (i.e., infiltration) rather than by whole-house mechanical ventilation systems, accurate understanding of the uses of blowerdoor data is critical. Blower doors can be used to answer the following questions:.

The aim of this paper is to discuss the impact of the relation between varying indoor and outdoor conditions on the ventilation loads of buildings and to provide HVAC designers with the respective information needed for the optimum dimensioning of the system. The total load generated by one litre per second of fresh air brought from the outside environment to the indoor space conditions, called -ventilation load index-, is calculated for the cities of Athens and Thessaloniki, Greece. The same principles can be applied to other locations.

This work evaluates the performance of different façade solutions, comparing simulation results of glass type and (internal and/or external) solar protection, in the cities of São Paulo and Rio de Janeiro, Brazil. For the simulations, it was considered as