XII Международная студенческая научная конференция Студенческий научный форум - 2020

Innovative ventilation systems.

Ventilation provides the best indoor climate.

A building’s ventilation is based on the pressure difference generated either by mechanical control or by natural ventilation jointly created by the temperature and the wind.

The functioning of natural ventilation depends on the weather. The supply air is not cleaned. It is also not energy-efficient, as you lose heat with the extract air.

Mechanical extract ventilation uses a fan to extract exhaust air. Heat cannot be recovered and there is not always enough make-up air.

In supply and extract air ventilation, the supply air is also blown inside mechanically. The supply air can be filtered and processed efficiently, and heat is being recovered from the extract air. This means that the method is energy-efficient.

We speak of air conditioning, when the supply air is also humidified or dried, cooled or heated, as required. This will ensure that the indoor air is always of uniform quality and healthy for us, regardless of changes in external and internal conditions.

Air conditioning seems to be a standard feature in almost all new cars these days. Why not in all apartments as well!

It is very difficult to implement a good indoor climate in an energy-efficient, air-tight building, without an efficient mechanical ventilation unit equipped with heat recovery.

The basics of a good Enervent indoor climate:

Health factor

The indoor air is fresh and filtered

The building is healthy and not moldy

The rotary heat exchanger returns humidity to the indoor air during winter, and thus always maintains the humidity of the indoor climate at a healthy level for both the building and its occupants.

Comfort

A suitable indoor air temperature is created by heating or cooling the air blown inside.

Controlling the humidity level of the indoor air also enables comfortable indoor conditions in hot summer weather or when it is very humid.

Energy-efficiency

A rotary heat exchanger is extremely energy-efficient, even on its own, and when combined with a heat pump, you have an energy-efficient solution with no equal. All surplus and waste energy can be harnessed by introducing the Aqua and EnergyBUS functions.

The summer night cooling of the rotary heat exchanger decreases the cost of cooling.

The carbon footprint and the payback period of the investment are both small.

Oxygen: Innovative ventilation system created by researchers.

Researchers working at Kaunas University of Technology (KTU) Startup Space are developing a silent and energetically efficient ventilation device (recuperator), which retains up to 89 percent of heat.

"Our innovation will provide fresh and clean air for your house without heat loss," promises the team of researchers behind the product called Oxygen. The main Oxygen's difference from standard ventilation devices is its small size.

"The device can be mounted above the ceiling -- thus it becomes invisible and inaudible, which is especially convenient for those living in small spaces," says Žilvinas Salialionis, the Oxygen Product Manager.

He says that the start-up was founded aiming to answer the current needs of the housing market. Last year, European Union has issued the recommendations to install mechanical ventilation systems in every new-built house. In flats there are often not enough space to accommodate a large ventilation device, therefore it was decided to create a compact product, which could easily fit in very small premises.

Oxygen is not only visually appealing, but also efficient in energy saving terms. The special air filtering system retains even the smallest, invisible particles, and the F7 class filter traps pollen, therefore the system is suitable for people suffering from allergies.

The team of KTU researchers has already introduced the prototype. At the moment the final refinements of the product are being made -- it is planned to introduce Oxygen to the market in the beginning of the next year.

Among the partners of Oxygen are global suppliers of components for ventilation devices, who, according to Mr Salialionis, are extremely helpful when overcoming challenges in the field and catching up with the new industry trends. The Oxygen Production Manager himself is an economist, who has been working with smart devices for many years, therefore is proficient not only in technical terms, but also has good knowledge of managing finances of the start-up.

Oxygen's technical solutions are being provided by the team of five mechanical engineers.

Low-Cost Ventilation in Production Housing.

When the U.S. Department of Energy’s Building America research teams began working with builders to design more energy-efficient homes, two things became clear in regard to ventilation: 1) high-performance homes require mechanical ventilation to bring in fresh air and to exhaust stale air for removal of localized pollutants, and 2) cost-effective, reliable systems for mechanically introducing fresh air did not exist.

Some builders choose an exhaust fan as the only form of mechanical ventilation in the home. Building America research has shown this is the lowest-cost approach that can meet ASHRAE 62.2 ventilation requirements. The fan should be low-sone rated for quiet operation and rated for low power draw. Both of these attributes are assured with ENERGY STAR certified fans. The fan should be set for continuous operation or timer-controlled for consistent periodic operation, and it should be ducted to exhaust outdoors, not into the attic.

Researchers noted the following limitations of exhaust-only ventilation systems. They draw outdoor air into the building through cracks and leaks in the building enclosure. Outside air that comes through garages, attics, crawlspaces, or walls may be contaminated with soil gases, dust, insulation, and other particulates.

If a house is very air tight, the exhaust fan may not be able to draw in as much air as it exhausts, thus the home can become depressurized. Any combustion appliances within the conditioned space should be sealed combustion to avoid back-drafting combustion gases. An exhaust-only system is less likely to achieve whole-house distribution of ventilation air, especially for closed or distant rooms, since the air is pulled from one location in the home and replacement air will typically be drawn through envelope leaks closest to this location.

To address these concerns, engineers at Building Science Corporation, a Building America research partner, invented and eventually commercialized a system that works with the home’s central furnace air handler and duct system to introduce and distribute fresh air in the home.

The central fan-integrated supply system draws in fresh air from an outside vent to the return side of the air handler plenum using the air handler fan and distributes it throughout the house. Building America researchers configured electronic controllers with an automatic timer that operates the fan periodically during periods when the thermostat is not calling for heating or cooling to ensure adequate outside ventilation air.

While the fan could be set for continuous operation, that would consume more electricity than necessary and would oversupply outside air in warm, humid climates (Rudd 2011). A motorized damper on the outside air intake limits outside air intake during periods of constant central fan operation, such as mid-summer or mid-winter.

Fan energy consumption can be reduced by one-half or more by using a central fan that has an electronically commutated motor (ECM), rather than a permanent split capacitor (PSC) motor. However, proper duct design to manufacturer’s specifications is critical to overcome airflow resistance at low speeds (Rudd 2011). The efficiency of the ventilation system can also be improved by using a properly designed duct system with right-sized, insulated, and air sealed ducts in a compact layout preferably located within the home’s conditioned space.

Exhaust fans are still needed to provide spot ventilation in kitchens and bathrooms. When the exhaust fans are operated continuously or intermittently on a timer in conjunction with the central fan-integrated supply ventilation, they provide a “semi-balanced” ventilation that is a simple, cost-effective alternative to heat/energy recovery ventilators.

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