Description:
The lack of professional information regarding reliability, quality and optimization of ventilation systems led to the appearance of a number research projects. One of these projects, Building Advent, was implemented in European countries in order to distribute information from designers about successfully implemented ventilation systems. Within the framework of the project, 18 public buildings were investigated, located in various climatic zones of Europe: from Greece to Finland.
The lack of professional information regarding reliability, quality and optimization of ventilation systems has led to a number of research projects. One of these projects, Building Advent, was implemented in European countries in order to distribute information from designers about successfully implemented ventilation systems. Within the framework of the project, 18 public buildings were investigated, located in various climatic zones of Europe: from Greece to Finland.
The Building Advent project was based on the instrumental measurement of microclimate parameters in the building after its commissioning, as well as on a subjective assessment of the quality of the microclimate obtained by surveying employees. The main parameters of the microclimate were measured: air temperature, air flow speed, as well as air exchange in summer and winters.
The Building Advent project was not limited to a survey of ventilation systems, since the quality of the internal microclimate and the energy efficiency of the building depends on many different factors including architectural and engineering solutions building. To assess the energy efficiency of the buildings, data on heating, ventilation and air conditioning systems, as well as other systems - thermal and electricity consumers are summarized. Below are the results of the estimation of three buildings.
Buildings representatives are located in three different regions with substantially different climatic conditions that determine the composition of engineering equipment.
The climatic conditions of Greece generally determine the high load on the cooling system; Great Britain - moderate load on heating and cold supply systems; Finland is a high load on the heating system.
Buildings representatives in Greece and Finland are equipped with air conditioning systems and central systems Mechanical ventilation. In the building located in the UK, natural ventilation is used, and the cooling of the premises is carried out due to night ventilation. In all three buildings, representatives allowed the possibility of natural air ventilation by opening windows.
The five-story office building, put into operation in 2005, is located in the city of Turku on the southwest coast of Finland. Calculated outdoor air temperature in cold period -26 ° C, in warm - +25 ° C with enthalpy 55 kJ / kg. The calculated temperature of the internal air in the cold period is +21 ° C, in the warm period - +25 ° C.
Picture 1. |
The total area of \u200b\u200bthe building is 6 906 m 2, the volume is 34,000 m 3. In the middle of the building there is a large atrium with a glass roof, in which a cafe and a small kitchen are located. The building is designed for 270 employees, but in 2008 180 employees operated regularly. On the first floor, an area of \u200b\u200b900 m 2, a workshop and storage facilities are located. The remaining four floors (6,000 m 2) are busy with office space.
The building is divided into five ventilation zones, each of which is equipped with a separate installation of central air conditioning, as well as cooling beams in separate rooms (Fig. 2).
The outer air is heated or cooled in the installation of central air conditioning, then it is distributed in the room. The heating of the supply air is carried out partially due to the recovery of the heat of exhaust air, partially through the calorificates. If necessary, the air in a separate room is additionally cooled by cooling beams controlled by room thermostats.
The temperature of the supply air is maintained in the convert +17 ... + 22 ° C. The temperature adjustment is carried out by changing the speed of rotation of the recovery heat exchanger and the regulating valves of the water flow of heating and cooling circuits.
The heating and cooling systems in the building are attached to the networks of central heat and cold supply on an independent scheme through heat exchangers.
Office rooms are equipped with water heating radiators with thermostatic valves.
Air consumption in office space is maintained constant. In the premises of the negotiable air flow variable: when using rooms, the air flow control is carried out according to the testimony of temperature sensors, and in the absence of people - air exchange decreases to 10% of regulatory valueconstituted 10.8 m 3 / h per 1 m 2 rooms.
The building is located in the central part of Athens.
In the plan, it has a form of a rectangle with a length of 115 m and a width of 39 m, with a total area of \u200b\u200b30,000 m 2. The total number of personnel is 1,300 people, more than 50% of which work in premises with a high density of staff placement - up to 5 m 2 per person.
The calculated temperature of the internal air in the cold period is +21 ° C, in the warm period - +25 ° C.
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Figure 3. Building in Greece |
The building was reconstructed in 2006 as part of the EU demonstration project. During the reconstruction, the following works were performed:
Installing sunscreen on the southern and western facades of the building to optimize heat gain from solar radiation both in cold and warm periods;
Double glazing of the northern facade;
Modernization engineering systems and their equipment by automation and dispatch systems;
Installation of ceiling fans in office spaces with high density staff placement to increase the level of thermal comfort and reduce the use of air conditioning systems; Ceiling fans can be controlled manually either through the automation system and dispatching of the building along the signals of the sensors of the presence of people;
Energy-efficient luminescent lamps with electronic control;
Variable consumption ventilation, adjustable by level of CO 2;
Installing photoelectric panels with a total area of \u200b\u200b26 m 2.
The ventilation of offices is carried out either by installing central air conditioning, or with natural ventilation due to opening windows. In office space with a large personnel placement density uses mechanical ventilation with variable air consumption, managed by testimony of CO 2 sensors, with adjustable supply devices providing 30 or 100% air flow. Installations of central air conditioning are equipped with air-heated heat exchangers to utilize the heat of exhaust air for heating or cooling the supply. To reduce peak refrigeration loads, the heat of the heat-intensive structural elements is used, cooled in the central air conditioning installation.
The three-story building is located in the southeastern part of the UK. The total area is 2,500 m 2, the number of personnel is about 250 people. Part of the personnel works in the building constantly, the rest are in it periodically, in temporary jobs.
Attachment and negotiations are held most of the building.
The building is equipped with sunscreen - visors located at the level of the roof on the southern facade to protect against direct sunlight in the summer. Photoelectric panels have been built into the visors to generate electricity. On the roof of the building installed solar collectors for heating water used in toilets.
The building uses natural ventilation due to windows opening automatically or manually. For low temperatures Outdoor air or on rainy weather windows are closed automatically.
Concrete ceilings of premises are not closed with decorative elements, which allows you to clutter them with night ventilation to reduce daily peak refrigeration loads in the summer.
In the building located in Finland, centralized heat supply is organized. The values \u200b\u200bof power consumption shown in Table. 1, were obtained in 2006 and adjusted with the actual degree of degree.
Cooling energy consumption was known because the building uses a central cooling system. In 2006, the refrigeration load was 27 kWh / m 2. To determine the cost of electricity to cooling, this value is divided into a refrigeration coefficient equal to 2.5. The rest of the electricity consumption is the total power consumption of OWK systems, office and kitchen equipment and other consumers, which cannot be divided into separate components, as the building is equipped with only one electricity metering device.
In the building located in Greece, the consumption of electricity consumption is carried out in more detail, therefore the total amount of electricity consumption is 65 kWh 2, includes 38.6 kWh / m 2 on lighting and 26 kWh / m 2 at all equipment. These data were obtained after the reconstruction of the building for the period from April 2007 to March 2008.
The power consumption of the building in the UK, as well as buildings in Finland, cannot be divided into components. The building is not equipped with a separate cooling system.
* Energy costs for heating and cold supply are not adjusted to the climatic characteristics of the construction region
During the study of the quality of the microclimate, temperature and air flow velocity were measured. The ventilation air consumption is adopted according to the commissioning of the building commissioning, since the building is equipped with a system with a constant flow rate of 10.8 m 3 / h per m 2.
Measuring the quality of internal air according to EN 15251: 2007, it is shown that the internal microclimate corresponds primarily to the highest category I.
Measurements of air temperature were performed for four weeks in May (heating period) and July-August (cooling period) in 12 premises.
Temperature measurements show that the temperature was maintained in the range of +23.5 ... + 25.5 ° C (Category I) for 97% of the construction period throughout the entire cooling period.
During the heating period, the temperature was maintained in the range of +21.0 ... + 23.5 ° C (Category I) during the clock use of the building throughout the entire period of observation. The amplitude of the temperature fluctuations in the working time was approximately 1.0-1.5 ° C during the heating period. The local criterion of thermal comfort (the level of drafts), the Fangor's comfort index (PMV) and the expected percentage of unsatisfied (PPD) were determined by short-term air velocity observations and temperature in March 2008 (heating period) and June 2008 (cooling period) in accordance with the standard ISO 7730: 2005. The results indicate a good common and local thermal comfort (Table 2).
Measuring air temperature was carried out in a building for six months in 2006. The air temperature in the premises exceeded +28 ° C in six observation points.
Measurements of CO 2 concentration fixed values \u200b\u200bin the range of 400-550 PPM with periodic peaks. Currently, additional observations are carried out in cold, warm and transitional periods. These observations include measuring air temperature, relative humidity and concentration of CO 2. Preliminary results show that temperatures are significantly lower than the initial measurements showed. For example, from June 24, 2008 to July 8, 2008, the temperature in the representative central points on the floors 1 and 3 exceeded +25 ° C throughout 4 hours, and the CO 2 concentration exceeded 700 PPM throughout 3 hours, with peaks below 800 ppm.
Typical air temperature values \u200b\u200bin summer period In office spaces make up +27.5 ... + 28.5 ° C. The number of hours with a temperature above +30 ° C was minimal. Even with extreme outer temperatures (above +41 ° C), the inner air temperature was constant and remained below the outdoor temperature at least 10 ° C. In the summer months of 2007 average temperature In the zones of the most dense placement of employees (up to 5 m 2 per person) lay in the range of +24.1 ... + 27.7 ° C in June, +24.5 ... + 28.1 ° C in July and + 25,1 ... + 28.1 ° C in August; All these values \u200b\u200bdo not go beyond the range of thermal comfort.
Throughout the period of observation (April 2007 - March 2008), the maximum values \u200b\u200bof the concentration of CO 2 above 1,000 ppm were recorded in many areas of the most dense placement of employees. CO 2 concentration exceeded 1,000 PPM in 57% of the observed points in June and July, in 38% of offices in August, 42% in September, 54% in October, 69% in November, 58% in December and 65% in January. Among all office premises, the highest concentration of CO 2 was marked in offices with the maximum density of users. However, even in these zones, the average concentration of CO 2 was in the range of 600-800 PPM and corresponded to the ASHRAE standards (maximum 1,000 PPM for 8 continuous hours).
In the building located in Finland, most of The premises are not equipped with individual temperature regulation. The level of air temperature satisfaction was almost expected for offices without personal control. The level of satisfaction with the general microclimate, the quality of internal air and the lighting was high.
In the building located in Greece, most of the employees were not satisfied with the temperature and level of ventilation at workplaces, but it was more satisfied with the lighting (natural and artificial) and noise level.
Despite the identified problems with temperature and air quality (ventilation), most people have a positive assessed the quality of the internal microclimate.
Building in the UK is characterized high levels Satisfaction with the quality of internal microclimate in the summer. Heat comfort in the winter was estimated as low as low, which may indicate problems with a draft in a building with natural ventilation. Also, as in Finland, the level of satisfaction with acoustic comfort was low.
| Table 3. Subjective quality assessment microclimate premises According to the results of employees surveys |
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The results of studies of three buildings show that employees are more satisfied with the quality of the microclimate in the summer in a building with natural ventilation without cooling (United Kingdom) than the quality of microclimate in the office equipped with a central air conditioning system with high ventilation air exchange values \u200b\u200b(10.8 m 3 / m 2 ) and low density of employees (Finland). At the same time, in the building in Finland, according to measurements, excellent quality of the internal microclimate.
The speed of air flow and the levels of drafts were low, and the internal climate was rated as the corresponding highest category according to EN 15251: 2007. Given this measurement data, it is surprising that the level of user satisfaction was below 80%. Partially these results can be explained by a very low level of satisfaction with acoustic comfort. It is likely that some users do not feel comfortable in large office space, and the absence of the possibility of individual temperature control can increase dissatisfaction with thermal comfort.
Research results have shown that in buildings-representatives, elevated ventilation air exchange does not have a significant effect on energy efficiency: the consumption of thermal energy in the building located in Finland was lower than in the building in the United Kingdom. This observation demonstrates the efficiency of recycling (recovery) of the heat of the ventilation air. On the other hand, the research results show that a significant proportion of energy consumption is the costs of non-thermal energy to heating and cold supply, but electrical energy for cooling, lighting and other needs. The best accounting and optimization of power consumption is implemented in a building located in Greece, which indicates the need for a more thorough development of projects in terms of power supply. As a priority event, it is advisable to improve the quality of the accounting of power consumption.
Reprinted with abbreviations from Rehva Journal magazine.
Scientific editing performed by Vice President NP "Avok" E. O. Schilkerm.
The efficiency of air circulation determines the quality of the microclimate in the room, on which the level of comfort and general human well-being depends. Air inside the room should be responsible for certain norms of oxygen and carbon dioxide. To achieve and maintain optimal atmospheric parameters, the ventilation system is equipped. Installation of the ventilation complex requires a professional approach and special knowledge from the artist.
The ventilation system is a complex of equipment and measures to ensure sufficient air circulation. the main task Ventilation is an output from the premises of the "spent" and filling it with a flow of fresh air. Each system can be described in four basic signs: the appointment, method of movement of air masses, constructive features and scope of application.
IN apartment houses Predestly uses natural ventilation. Air circulation is carried out under the influence of pressure drops and temperatures. The principle of functioning of a natural air exchange is often implemented in private houses.
The popularity of natural circulation is due to the number of advantages:
Fundamental device ventilation system Natural type is presented in the diagram. For the functioning of the complex, exhaust and supply channels are required, providing free air movement.
Valing scheme:
If the performance of natural circulation is not enough, the installation of a mechanical ventilation system is necessary. For removal and supply of air flow, special equipment is used.
In complex systems, the incoming air may be processed: drain, moisturizing, heating, cooling or cleaning.
Enforcement systems are usually used in production, in office and warehousesWhere high-power ventilation is required. The complex consumes a lot of electricity.
Comparative advantages of mechanical ventilation:
Mechanical air exchange implement in several ways:
The most rational is the supply and exhaust complex. The system has two independent flow of expulsion and air supply connected by ventilation. The main components of the complex:
The system may include: air heaters, humidifiers, mancraft and dryers. Structurally, the device is performed in a monoblock or team form.
Principle of operation of the ventilation system:
Types of special purpose ventilation systems:
When planning a ventilation system, it is necessary to proceed from the requirements of sanitary rules and norms put forward by the premises of various purposes. Fresh air supply standards are given per person.
Basic standards are shown in the table.
In office premises, the focus is on the rooms where staff is located. So, in the office is sufficiently considered to replace air in the amount of 60 cubic meters. m / h, in the corridor - 10 cu. m, in a smoking room and a bathroom - 70 and 100 cubic meters, respectively.
When organizing a ventilation system in an apartment or private sector, focus on the number of residents. According to sanitary standards, the air exchange must be at least 30 cubic meters per person. If the housing area does not exceed 20 sq. M, the placement of the room is taken as the basis of the calculation. One meter square should account for 3 cubic meters.
The project of the ventilation system in a private house must be developed at the construction stage. In this case, it is possible to do a separate room under the ventilation chamber, to determine the optimal places of pipe laying and create decorative niches under them.
Calculation and layout of the supply and exhaust complex is better to entrust professionals. The specialist will make up the technical task, taking into account the area and the number of rooms, the location and purpose of the rooms, the arrangement of the elements that increase the burden on the ventilation system (oven, bathrooms and fireplaces).
Important! Design requires a weighted, serious approach to determining the capacity of the equipment - this will allow you to organize a sufficient air exchange and at the same time do not "drive" the air is vigorously.
The power of the system depending on the multiplicity of air exchange is calculated, so: l \u003d n * ln, where:
The average performance of the complex for apartments is 100-500 sq. M / h, for private houses and cottages - 1000-2500 sq.m / h, for administrative and production buildings - Up to 15000 sq. M / h.
Based on the calculated power, the remaining characteristics of the ventilation systems are selected: the length and cross section of the duct, the size and number of diffusers, the performance of the ventilation unit.
The duct section is calculated by the formula: S \u003d V * 2.8 / W, where:
All technological process It is divided into such steps:
For work you will need:
The installation of air ducts are proceeding if the following requirements are made:
Order of installation of air ducts:
The most time-consuming process is the installation of air ducts. Requirements to assembly work Various Ventkanals are almost the same:
A number of requirements are put forward to the organization of natural circulation of air:
Exhaust ventilations should be placed in the following rooms:
In the rest of the premises, the influx of fresh air is carried out - through the slots in window Ramama. With mass introduction of plastic window structures Effective supply natural ventilation Very decreased. To increase its performance, it is recommended to mount the supply walls or window valves.
The wall suction is a cylindrical flask, inside which is a heat-noise insulating insert, filtering element and air duct. The bandwidth of most models is 25-30 cubic meters per hour with a pressure drop of 10 Pa.
Mounting the wall valve:
The selection should be periodically brushed from dust, soot and small dirt particles. The filter element is enough to rinse under running water and install it in place.
Principle of operation of natural air circulation: video.
In modern design practice, specialists increasingly have to deal with such situations when technical solutions proposed by the market significantly overtake existing norms. For the designer, this situation may end in difficulties when agreeing the project. For the manufacturer, it is much more challenged - the inconsistency of the standards is even obviously winning and favorable solution It may turn out not only the loss of the market, but also by the stagnation of scientific and technical studies, which are the predominant investment destination from advanced companies.
However, such a challenge can be taken, without frightened the solar rules and putting forward to the market clearly advanced its development, and the norms change independently, forcing it to listen to themselves on the basis of the company's professional reputation. A specific example is the Flakt Woods initiative, one of the products of which are axial inkjet fans for Parking Jet Trans Funs.
JET TRANS FANS.
The traditional solution for the ventilation of underground parking, implemented with us everywhere, is box ducts, providing air exchange and smoke removal, smoke receivers, fireproof valves, etc. In existing regulatory practice, the supply and exhaust installations With your ducts. Until recently, the designers in Moscow were guided by the regional standards of MGSN 5.01 "Parking of passenger cars", which prescribed to separate the ventilation system to the lower and upper zones.
Such a solution is extremely ineffective, since it also leads to excessive costs of materials, time consuming and long-term installation, the rise in the use of a plurality of fans. In addition, for a modern development, a decrease in the dimensions of parking in height due to laying air ducts, which adversely affects the general effective use square meters.
Solves these problems a new solution for parking ventilation systems from Flakt Woods. This company is a famous professional in air conditioning and ventilation systems. Even the tunnel under the strait of La Mans is ventilated with only two fans, and those are from Flakt Woods. True, the problems of removal of the tanned air is not worth it. In the entire length of the 50-kilometer tunnel - rail, and cars are moving on it on special platforms.
In other cases, the issue of removal of exhaust gases is sharply facing every designer who faces built-in parking. At the heart of the reactive thrust system - inkjet fans that exclude the laying of the air ducts and work in normal mode, and in the mode of ventilation for local smoke removal. Being only part of the parking ventilation system, they, however, provide those characteristics that are presented by Flakt Woods as their main advantages. This is the high performance of the entire system and low installation cost, low production costs and optimization of the parking space.
The entire complex includes a set of CO2 sensors, and the necessary software and hardware solutions that integrate signals from sensors and the operation of each fan individually.
Thanks to an integrated solution, a system based on inkjet fans can independently determine the number of cars in the parking lot (according to CO2 sensors) and adjust the loads and craving for specific fans, reducing energy consumption by the system and increasing the resource of the mechanisms.
The same actions, but already in an emergency, accordingly, increasing fan turns, the system will take place in the event of a fire, localizing the source, freeing the room from smoke and providing access to fire units to an emergency car.
However, in cases with complex modern technical solutions, the designer is usually faced with the need for additional calculations. Flakt Woods independently performs this computational part, based on the latest research and accurate knowledge of the features of the work of its fans.
It should also be noted that the traction jet fans Flakt Woods can work in a completely reversing mode - this means that the fan provides 100% thrust in both directions. This significantly reduces the time required to derive air from the parking lot. For comparison, it is possible to give data on fans with a feed vector of thrust, in which both directions are asymmetrical, in this case the efficiency of the reverse thrust due to the design of the fan blades is worse than 40%.
Cooling beams
However, modern technical solutions for ventilation in which breakthrough energy-efficient technologies are implemented are not exhausted by systems for parking lots. In the commercial segment, cooling beams are becoming increasingly distributing - devices for firing or air cooling with water and with air distribution function.
The demand for cooling beams increases due to the increasing requirements of users to air quality in rooms, temperature, humidity, oxygen content, and noise level from annotation. At the same time, the requirements of the equipment and energy consumption of equipment are increasing, to the environmental consequences of the operation of systems, to the cost of operation and the flexibility of the system in relation to changing conditions.
For business centers, public buildings and hotels, the cooling beam-based ventilation solution is optimal. In such premises, the number of people in the same room is often changing, the air temperature and CO2 concentration drops quickly. Accordingly, the operation of the ventilation system in constant mode to carry out all the premises would lead to too much energy consumption.
Flakt Woods cooling beams have adjustable nozzles, due to which air can be supplied through the beam in the desired amount for specific situation. Flexible adjustable nozzles can create the necessary air flow in the room, forming various comfort zones depending on the placement of people or equipment in the room. In addition, the power supply control system of the electricity beam allows you to control air consumption based on CO2 sensors or presence sensors.
Twin Wheel
However, the main problem of cooling beams is condensate. In the case of cooling beams, when designing ventilation systems, it is necessary to solve the problem of additional air drainage to prevent flow. Engineers Flakt Woods have developed a more optimal solution that has received the name Twin Wheel. In terms of its action, the system is similar to a rotary heat recovery, which provides not only heat transfer, but also humidity. The system includes two rotors and a cooling heat exchanger, as well as automation and sensors, controlling the operation of the rotors in accordance with the specified values \u200b\u200bof the dew point.
In the primary circuit of such an allocation, the absorption rotor of complete disposal reduces the outdoor air temperature and provides moisture transmission from incoming air to remote. After passing through the primary rotor, the air temperature decreases in the cooling heat exchanger, the moisture condensation occurs there. Finally, dry and cooled air enters the ordinary rotor, where the heat of the air of the removed air and heated inlet occurs.
Thanks to the use of the system, the humidity of the supply air does not exceed the permissible levels and excludes the risk of condensation. Using the TWIN WEEL system, the cooling heat exchanger power can be reduced by 25%, which, of course, affects the overall power consumption of the entire annotation.
In this case, all the possibilities and advantages of cooling beams are not fully manifested, if we are talking about large business centers or hotels with many rooms of various purposes and rapidly changing loading. In this case, it is important to ensure the temperature control and pressure in the entire system. In addition, the optimal combination of water and air equipment It will reduce the energy costs of the system and extend the equipment resource.
For such situations, decisions regarding air supply in certain premises is better to take centrally, consistently analyzing data from sensors in different rooms and user requests for individual heating conditions or air cooling. The Flakt Woods solution for the integrated linkage of all components of the ventilation system is called IPSUM.
This is a comprehensive automation system that allows you to optimally configure the operation of all regions of the ventilation, to reduce energy consumption and increased comfort, and also provides considerable amenities for the operating organization for the management, maintenance and repair of the ventilation system.
One of the latest innovations in the field of ventilation systems in Flakt Woods is associated with the acquisition of the American leader in the field of heat recovery - the SEMKO company. The most famous technical solution Under this brand is a hygroscopic rotor for air recuperators. Due to the special polymer coating, such a rotor absorbs moisture out of the air, thus reducing the traditional disadvantages of rotary recoveors - small capabilities for cold recovery and transfer of odors. A hygroscopic rotor will help the juncture to work effectively in the summer, additionally cooling the air due to moisture transfer.
