Ways to improve the energy efficiency of ventilation systems

The article presents the search for possible solutions to save and improve energy consumption. Energy efficiency of buildings through the use of energy-efficient systems of ventilation. Overview and analysis of various energy-efficient ventilation systems. Advantages and disadvantages.

Keywords : energy efficiency, energy saving, energy efficiency indicators, energy saving in buildings, ventilation systems, recuperation.

В статье представлен поиск возможных решений по экономии и повышению энергопотребления. Энергоэффективность зданий за счет использования энергоэффективных систем вентиляции. Обзор и анализ различных энергоэффективных систем вентиляции. Преимущества и недостатки.

Ключевые слова: энергоэффективность, энергосбережение, показатели энергоэффективности, энергосбережение в зданиях, вентиляционные системы, рекуперация.

One of the main factors that can create favorable conditions for people's life and work is effective ventilation of the room. The main and very important design features to ensure the standardized operation of the ventilation system of buildings. Ventilation is a kind of complex schemes that include various elements, such as with air injection device, muffler, air ducts, grilles, etc.

Usually when designing ventilation the default settings are provided in the simplest way, providing the following specified conditions designers make appropriate design and planning decisions for buildings and try to reduce system performance by introducing technological processes with minimal harmful emissions, equip shelters for dangerous dumping sites [1].

Energy efficiency of housing construction includes a number of measures, to reduce the consumption of thermal energy by buildings necessary to maintain in the complex of necessary parameters of proper technological economy and microclimate justification of current activities and safety [2].

Everything seems simple: the less heat a building loses, the less energy it needs to compensate for heat loss. Therefore, at first glance, the simplest and most reasonable way to save energy for heating is to increase the heat-protective properties of the enclosing structure [4]. The desire to build buildings with low temperatures this has led to increased requirements for the thermal protection properties of enclosing structures (in Europe the 70s of the last century in Russia since the 2000s). About the requirements for walls and coatings the heat transfer resistance increased from 150–200 % to a window by 20–30 %, while for requirements the reduction of energy consumption for ventilation was ignored [2]. Is required an important parameter is the air exchange in the room, which provides an optimal level of microclimate in the room. During ventilation, internal impurities, bacteria, excess moisture are removed. In addition, an optimal ratio of oxygen and carbon dioxide concentration is maintained [3]. As in winter, in summer energy is also spent on cooling and heating well-ventilated air. When compiling an energy passport, the cost of ventilation in modern buildings is estimated as follows: 40–50 % of all heating costs [2]. And no matter how insulated the building is, you can save on ventilation. This cannot be achieved without the introduction of special engineering measures. And vice versa, the more important heat savings, more energy is spent on maintaining the necessary parameters of the microclimate [5,9–10,12–13].

Next, there are two main ways to improve the energy efficiency of residential buildings. With the help of different ventilation systems are considered:

1. Application of supply and exhaust ventilation systems with recuperation

It is these systems that are often considered as an energy-saving method, in which the air coming out of the building is used for pre-cooling in the hot season and heating the supply air in cold periods with a reduction in energy costs for heating the supply air. [4] । Plate, rotary and other recuperators are used for recuperation.

Рис. 1. Приточная установка с рекуперацией [6]

Plate pickers. The incoming and outgoing air passes from both sides of the row of plates. Here, the contact of supply and exhaust air is practically excluded. Such recuperators should be equipped with condensate outlets, as it is possible that it will form on the plates. Condensation can lead to the formation of ice, so a defrosting system is needed. Heat recovery can be controlled by a bypass valve that regulates the flow of air passing through the heat exchanger. The plate heat exchanger has no moving parts [5].

Rotary recuperators. In them there is a complete exchange of temperatures of both air flows. Heat exchange is carried out through a constantly rotating rotor between the sample and the feed channels. Such recuperators have a significant drawback, which is that odors and pollutants released by people, furniture, building materials can pass from exhaust air to supply air. The correct arrangement of the fans eliminates this disadvantage. The level of heat recovery is regulated by the speed of rotation of the rotor. Rotary recuperators have moving parts [5].

Indoor retrievers. The curtain will divide the room into 2 parts. The exhaled air heats part of the chamber, then the flap changes the direction of the air flow so that the supply air is heated by the heated walls of the chamber. The disadvantage is that pollution and odors contained in the exhaust air can be transmitted to the power source.

Recuperator with intermediate coolant. They are usually used in systems where mixing of air flows is unacceptable, as well as in cases of large distances between supply and exhaust installations.

The heat carrier receives heat from the exhaust air through a heat exchanger installed in the exhaust part and transfers it to the supply air through a heat exchanger installed in the supply part of the installation, which performs the function of a starting heater. Depending on the climate, water or a non-freezing liquid is used as an intermediate refrigerant, most often distilled water contains a 40 % solution of ethylene glycol.

Heat pipe. This recuperator consists of a closed system of filled freon tubes, which evaporates due to the heat generated by the exhaust air. Freon is supplied by a heat exchanger (condenser) located in the supply part of the installation and condensate, which provides heating with supply air.

2. Adaptive ventilation system with variables a ir f low

The system ensures the maintenance of the set air parameters in the following service areas. Various microclimate requirements at a relatively affordable price fan power consumption. Energy efficiency is achieved due to the principle by which such systems work, namely ventilation, when and where they are needed [6,17].

The elements of the ventilation system work according to the needs of each room, the number of people and the type of activity. There are three main types of adaptive systems: motion sensors that can be adjusted manually, as well as sensors that register changes in humidity and carbon dioxide concentration.

Ventilation systems with humidity sensors are best suited for residential buildings. Humidity is also a relative indicator of the level of pollution in the room. The amount of moisture directly depends on human activity. A family of four people in the form of steam releases about 10–15 liters of moisture per day (bathing, washing, cooking, breathing and physical activity activity). This moisture must be removed from the room. Otherwise, it will condense Mold will develop on the walls, behind cabinets and in the corners of the room. [8]

Components that react depending on the increase/decrease in humidity and the ventilation system. There is the ability of some materials to expand with an increase in air humidity and shrink with a decrease in air humidity. The airflow is adjusted according to the humidity inside the larger the room, the wider the shutters that control the amount of incoming airb the room is open. The humidity sensor is completely isolated from the supply air and records. Only the internal humidity changes. Moisture sensitivity technology is used power supply, exhaust grille of the room, which shows the level of humidity conditions internal pollution (living room, bedroom, kitchen, bathroom)

Living room with a great need when using adaptive ventilation systems. An empty room receives more air flow than [9].

Ventilation systems with motion sensors are often used in public places. For example, they are convenient for fitness clubs.

An economically viable way to increase energy efficiency is to use a set of measures such as increasing the thermal protection of enclosed structures, the introduction of engineering and construction measures, and modern energy-saving methods and technologies [10–11]. Already, many facilities do not meet the recently adopted thermal engineering requirements. There will be more within 5,10 years. We need to find new ways to increase

Energy efficiency, construction and construction implement advanced technology [9, 11–13]. It is necessary to take into account the already known structural, optical, thermophysical and acoustic deficiencies. In the future, they will have to adapt to different needs human life support [12–13].

References:

1. Karadzhi, V.G., Moskovko Yu.G. Some features of effective use of ventilation and heating equipment. Manual — M., 2004
2. Gorshkov A. S. Energy efficiency in construction: issues of rationing and actions to reduce energy consumption of buildings // Civil Engineer magazine. 2010. No. 1. pp. 9–13.
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5. Tauroginsky V. I. Experience in the construction of energy-saving buildings in Belarus // Energy saving. 2008. No. 1. pp. 74–78.
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10. Nemova D. V. Hinged ventilated facades: overview of important issues // magazine. 2010. No. 5. pp. 7–11.
11. Protasevich A. M., Krutilin A. B. Сategorization of ventilated front systems. Impact of heat-conducting accessions on their thermal protection characteristics // Civil Engineering magazine. 2011. No. 8. pp. 57–62.
12. Vatin N. I., Nemova D. V. NVF: the main problems and their solutions // The world of construction and real estate. 2010. No. 36. pp. 2–4.