Laboratory ventilation systems are designed to isolate and protect occupants from hazardous fumes and at the same time provide outside air at comfortable conditions. This often results in high air flow rates whereby the electrical fan energy use can be very high. For the building described in the paper, the fan energy use is 44% of the total electricity use in the building.
This guide is part of a series on best practices for laboratories and focuses on the use of low-pressure air distribution systems.
Decision makers that have to decide which type of HVAC system that has to be installed in a building, will usually base their decisions on the investment and running costs (including expected maintenance costs) and their perception of the quality of the system. In general, the energy savings will be compared to a reference (less efficient) system to calculate the benefit. However, the choice of the building equipment has also an impact on the Indoor Environmental Quality (IEQ) and on the performance of the workers inside the building.
Submitted by Maria.Kapsalaki on Thu, 09/19/2013 - 00:04
For the past 50 years, a wide variety of building energy simulation programs have been developed, enhanced, and are in use throughout the building energy community. This report provides an up-to-date comparison of the features and capabilities of twenty major building energy simulation programs: BLAST, BSim, DeST, DOE-2.1E, ECOTECT, Ener-Win, Energy Express, Energy-10, EnergyPlus, eQUEST, ESP-r, IDA ICE, IES <VE>, HAP, HEED, PowerDomus, SUNREL, Tas, TRACE and TRNSYS.
This document proposes a classification of the concepts of ventilated double facades, also referred to hereafter in this document as "VDF". The main classification adopted here (see Part 2) offers a coherent solution for unambiguously describing the various VDF concepts encountered in practice. In order to integrate oneself into the international context, various classifications used in the literature were considered before developing this proposal. A great deal of work was done in order to clarify the terminology associated with these facades.
When an obstruction is present in a ventilation ductwork, the noise level may be considerably higher than the level measured without the obstruction. This excess noise is due to the interaction of the flow with the element and it is called flow-generated noise in the element. Numerous examples may be found in the literature where this mechanism occurs, such as flow noise generated in duct elbows, dampers, grilles, louvers, duct discontinuities. It reduces the attenuation performance of dissipative silencers and is responsible of the well-known aeolian tones of wires and rods.
Fans are used in many industrial, building and household applications, especially for ventilation, and are often considered as particularly noisy components. A large amount of work has been carried out for improving knowledge on fan noise generation and finding noise reduction means. These researches mainly rely on works initially performed on rotating machinery used for instance in aeronautic applications, but significant differences exist between the noise mechanisms of high speed fans of aircraft engines and those of low speed domestic or industrial fans.
Submitted by Maria.Kapsalaki on Wed, 09/18/2013 - 17:34
Air supplied by ventilation plants and air conditioning systems carries small particles whose size depends on filtration device efficiency.
Mineral, vegetal or biological particles may deposit on the inner surface of air ducts and other air conditioning equipment creating a thin layer of dust. Such dust deposit may deteriorate the quality of the air flow blown into the rooms through the booths and consequently the global indoor air quality in the building.
Submitted by Maria.Kapsalaki on Wed, 09/18/2013 - 17:33
The role of CO2 to control the indoor air quality in buildings is based on the fact that CO2 developed by people breathing may be used as a marker for the bio-effluents produced by people. The use of CO2 for the steering of ventilation systems is only appropriate in the case that no other pollutant is more dominant for the indoor environment. For instance when a person is taking a shower in a bathroom, moisture will be the more dominant pollutant. Nevertheless the use of CO2 as marker for the indoor air quality is widely used.
Submitted by Maria.Kapsalaki on Wed, 09/18/2013 - 17:32
For the near future the expectation of experts is that the most promising systems will be based on demand-controlled hybrid ventilation technologies. The impact of further development and the improvement of fully mechanical or fully natural ventilation systems on energy savings and indoor air quality is reaching its limits. The hybrid part of the system is of course the minimisation of the electric power of the fan by improving the fan efficiency and low pressure ducting.
Born with the energetic crisis, humidity controlled ventilation has been introduced in regions with a moderate climate as a means to fight condensation problems induced by tighter building construction and lower heating temperatures.
This paper develops the means and goals of humidity controlled ventilation in the framework of the building energy reduction.
Why have a variable airflow?
Why chose humidity as the driving parameter?
How does humidity controlled ventilation work?