The use of decentralized ventilation systems with heat recovery in the historical buildings of St. Petersburg

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1 Applied Mechanics and Materials Submitted: ISSN: , Vols , pp Accepted: doi: / Online: Trans Tech Publications, Switzerland The use of decentralized ventilation systems with heat recovery in the historical buildings of St. Petersburg Vera Murgul 1,a, Dusan Vuksanovic 2,b, Nikolay Vatin 3,c, Viktor Pukhkal 4,d 1,3 St. Petersburg State Polytechnical University, Politekhnicheskaya ul., 29, , Saint-Petersburg, Russia 1 Faculty of Architecture in Podgorica, University of Montenegro, Cetinjska br , Podgorica, Montenegro 4 St. Petersburg State University of Architecture and Civil Engineering, 2-Krasnoarmejskaja ul. 4, St. Petersburg, , Russia a october6@list.ru, b dusan.vuksanovic@gmail.com, c vatin@mail.ru,, d pva1111@rambler.ru Keywords: mechanical ventilation; heat recovery; air-to-air plate heat exchanger, energy efficiency, reconstruction, thermal balance, building. Abstract. Historic apartment buildings in Saint-Petersburg no longer meet today s energy efficiency standards and need upgrading to achieve lower energy-consumption. The possibilities to upgrade old buildings historic and cultural monuments are initially limited. A controlled heat recovery ventilation system is considered to be an integral part of energy efficient building. Provided engineering facilities of a building are updated and reequipped energy performance increases without any impact on building exteriors. Different types of decentralized intake and exhaust ventilation systems with heat recovery based on various types of heat exchangers are considered in a detailed way. Introduction There is a range of aspects forming a ground to implement complex energy efficient reconstruction of old buildings as follows: growth of deterioration of old buildings, aging of engineering equipment, non-compliance with the existing rules and regulations related to energy consumption [1, 2, 3]. Dwelling historic buildings are considered to be specific objects with particular requirements for reconstruction and renovation. First and foremost exteriors of historic buildings should be remained the same since they are distinctive ones and recognized as historical and cultural monuments. Another reason is a must to leave authentic urban environment of a historical center as it is [4, 5]. Reconstruction is a seldom used activity in a life cycle of a building. Planned reconstruction and renovation of old buildings should be combined with a set of measures to be taken to improve energy performance [6, 7]. State and value of structural members of old buildings set the limits on possible changes and modifications to be implemented in the course of energy efficient reconstruction [8]. A set of measures for energy improvement of existing buildings includes a range of basic aspects. Energy efficiency concept is presented in the Figure 1. All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans Tech Publications, (ID: , Pennsylvania State University, University Park, USA-21/02/16,06:05:07)

2 Applied Mechanics and Materials Vols Figure 1. Concept of energy efficiency in buildings. It s often impossible to make changes to walling when upgrading historic buildings. First of all it is related to supplementary technological equipping of building envelopes, for instance solar power supply modules [9, 10]. However a range of measures can be taken in most cases: thermal insulation of walling, elimination of thermal bridges, air sealing of joints in all the envelopes, installation of heat recovery ventilation systems, use of energy efficient equipment [11, 12, 13]. According to studies [14, 15, 16, 17, 18] nearly half of heat losses are caused by filtering through building envelopes, and the other half of heat losses occur due to ventilation emissions (Figure 2). A significant influx of heat can be reached due to passive solar heating and domestic heat recovery in ventilation systems Figure 2. Thermal energy balance in buildings. Energy efficiency classes in terms of thermal energy consumption for heating buildings are set by existing Russian rules for thermal protection of buildings (Figure 2). It is possible to reach energy efficiency class A provided the whole set of measures to improve energy performance are taken. In particular heat recovery is a must. Besides, sealing of buildings sets

3 372 Advanced Design and Manufacturing Technology IV the grounds for a controlled ventilation system to be used with the purpose to ensure appropriate air exchange rate. Conventionally, natural ventilation systems were arranged in historic buildings. The background of their usage gives the evidences of negative impacts related to deterioration of air quality (especially in the case of buildings supplied with gas), thermal and humidity abuse in rooms. Problems with air exchange in apartments of multi-storey buildings are caused by disadvantages of natural ventilation systems [19, 20, 21, 22]. Use of decentralized intake and exhaust ventilation systems with heat recovery could be a good solution for low-rise historic buildings of Saint-Petersburg (3-5 storey houses). Decentralized ventilation systems in residential buildings and apartments The first type of a decentralized ventilation system is an apartment one. In this case separate individual single-block intake and exhaust ventilation systems with cross-flow plate-based heat exchangers are installed in every apartment (Figure 3). An air ductwork is arranged throughout every apartment. Air intake into apartments is supposed to be arranged through air diffusers, and air recovery is supposed to be arranged in kitchens, toilets and bathrooms. Outer air is heated in a heat exchanger by the air recovered from an apartment. Figure 3. Decentralized air intake and exhaust mechanical ventilation systems with heat exchangers. [taken from 19] One of the measures to improve energy performance of buildings can be installation of decentralized air intake and exhaust mechanical ventilation systems with plate heat exchangers in apartments making it possible to «return» up to 85% of thermal energy (Figure 4). Fans have a possibility of 9-stage digital regulation [20]. Figure 4. Scheme of a mechanical air intake and exhaust ventilation system in apartments.

4 Applied Mechanics and Materials Vols Residents may change air exchange levels from 0 to 9 (the value 0 implies that the system is switched off; the values 1, 2, 3 are optimal for all the types of apartments and ensure the standard level of air exchange depending on the area of apartments, the values above 3 can level air exchange up but increase the level of noise). It is necessary to meet all the regulatory requirements for air exchange before to put energy efficient building into operation. To achieve this aim the following intake and exhaust air consumption rates have been regulated: 110 m 3 /h is for 1-2 room apartments, 130 m 3 /h is for 3- room apartments and 180 m 3 /h is for 4- room apartments. The balance of air consumption in intake and exhaust channels has been regulated with due account for standard exhaust air volumes in kitchens and toilets [20]. A controlled air exchange system makes it possible to save energy due to management of ventilation at different times of the day. Air exchange level can be limited up to 50% of the standard rate for those residents who work over 70 hours a week and are outside the building (at work, in a shop, or absent for a walk). The major problem to be solved when operating ventilation systems of this type is to prevent a heat exchanger from icing in winter time. Operating modes of the system are presented in the Figure 5. It is possible to achieve maximum energy performance of the system only if the temperature level of outer air is equal or lower than minus 10 С. When there is the lower temperature level additional measures to avoid acing should be taken. In this case energy efficiency decreases as well. Figure 5. Operating modes of an intake and exhaust ventilation system with plate heat exchangers. [taken from 19] The second type of decentralized ventilation systems to be recommended is an apartment ventilation system with recovery and regenerative heat exchangers. One of such systems with plate heat exchangers is presented in the Figure 6 [21]. The system is installed inside a building on an external wall, air intake is arranged through a horizontal slot in this wall, and the system components are mounted on the wall or inside an alcove of the wall which has already been prepared. Basic functions of such systems are as follows: - air is taken in and exhausted from an apartment simultaneously with heat recovery and noise protection provided; in this case efficiency of a heat exchanger amounts up to 73%; - intake air is been eliminated from dust; - as soon as the system is switched off an air admittance valve closes automatically; - a level of production of a 10-stage system is regulated with a remote control panel; - it provides a possibility to program individual parameters of the system.

5 374 Advanced Design and Manufacturing Technology IV Figure 6. Air intake and exhaust ventilation system with plate heat exchangers used in apartments. [taken from 21] 1 body; 2 a display control panel; 3 a front dashboard; 4 a supply air fan; 5 a heat exchanger; 6 a filter; 7 outer air supply channel and inner air removal channel; 8 an exhaust air fan Ventilation systems with heat recovery and regenerative exchangers used in apartments normally consist of an air supply (intake) grille placed in a room, an axial fan, filters to clean air up, a ceramic thermal conductor and an external grille with fixed blinds. A reverse axial fan alternately pumps exhaust air from rooms and intake air from streets through a regenerator. Exhaust air to be recovered transfers heat to a thermal conductor, and then intake air is heated through a regenerator. Both elements should work synchronically to make ventilation efficient. One element is in charge for air intake, and another one is in charge for air exhaust. A proper operation of both elements makes it feasible to ventilate straightway two rooms connected with air transfer grille in the area of doors or with the help of a duct placed beneath (Figure 7). Efficiency of such systems can amount to 97%. Figure 7. Scheme of a decentralized mechanical air intake and exhaust ventilation system with single-flow heat recovery and regenerative heat exchangers [taken from 22]. 1 intake (exhaust) system There is another type of such a system consisting of two fans and heat exchangers (double-flow) set in one body which operate alternately to supply and exhaust air (Figure 8).

6 Applied Mechanics and Materials Vols Figure 8. Scheme of a decentralized mechanical air intake and exhaust ventilation system with double-flow heat recovery and regenerative heat exchangers [taken from 22] 1 intake (exhaust) system; 2 intake (exhaust) system elements set in one body One of the reasons to use decentralized ventilation systems in apartments of historic buildings to be reconstructed is that there are available Z-shape channels in external walling of historic buildings which allow supplying outer air directly into dwelling apartments (Figure 9) [23, 24]. Summary Figure 9. A slot in a wall of an apartment designed for ventilation, a façade fragment. Decentralized intake and exhaust ventilation systems with heat recovery exchangers can be considered to be an efficient way to reduce thermal energy consumption required to heat and ventilate historic apartment buildings. It is often not allowed to make any changes and modifications to exterior walling of historic apartment buildings that makes it complicated to achieve energy upgrading in these buildings Upgrading engineering systems of the buildings, and in particular installation of heat recovery ventilation systems, has no impacts on external appearance of historic buildings and ensures significant energy performance gain. References [1] V. Murgul: Features of energy efficient upgrade of historic buildings (illustrated with the example of Saint-Petersburg). Journal of Applied Engineering Science, Vol. 12 (1) (2014), pp 1-10 [2] V. Murgul: Improvement of the energy efficient properties of the houses in the historical area of Saint-Petersburg, Architecton: Proceedings of Higher Education, 4 (40) (2012), pp [3] E. Aronova, G. Radovic, V. Murgul, N. Vatin: Solar Power Opportunities in Northern Cities (Case Study of Saint-Petersburg). Applied Mechanics and Materials. Vols (2014), pp [4] N. I. Vatin, A. S. Gorshkov, D. V. Nemova: Energy efficiency of envelopes at major repairs. Construction of Unique Buildings and Structures. 3 (8) (2013), pp [5] S. Golovina, V. Murgul: Solar energy systems in the architecture of historic cities. Bulletin of Civil Engineers. 5 (40) (2013), pp

7 376 Advanced Design and Manufacturing Technology IV [6] E. Juodis: Extracted ventilation air heat recovery efficiency as a function of a building's thermal properties, Energy and Buildings, Vol. 38, Issue 6, (2006), Pp [7] A. S. Gorshkov, P. P. Rymkevich, D. V. Nemova, N. I. Vatin: Method of calculating the payback period of investment for renovation of building facades. Construction of Unique Buildings and Structures. 2 (17) (2014), pp [8] V. Murgul: Solar energy in the reconstruction of urban environment of historic building Saint-Petersburg, Architecture and Modern Information Technologies, 2 (23) (2013), pp [9] G. Radovic, V. Murgul, N. Vatin: Fast urban development of Cetinje old royal capital of Montenegro. Applied Mechanics and Materials. Vols (2014), pp [10] N. I. Vatin, D. V. Nemova: Increase of power efficiency of buildings of kindergartens. Construction of Unique Buildings and Structures. 3 (2012), pp [11] C. A. Hviid, S. Svendsen, Analytical and experimental analysis of a low-pressure heat exchanger suitable for passive ventilation, Energy and Buildings, Volume 43, Issues 2 3, (2011), Pp [12] D. Nemova, V. Murgul, A. Golik, E. Chizhov, V. Pukhkal, N. Vatin: Reconstruction of administrative buildings of the 70s: the possibility of energy modernization. Journal of Applied Engineering Science, Vol. 12 (1) (2014), pp [13] J. Laverge, A. Janssens: Heat recovery ventilation operation traded off against natural and simple exhaust ventilation in Europe by primary energy factor, carbon dioxide emission, household consumer price and exergy, Energy and Buildings, Volume 50, (2012), pp [14] V. Murgul: Capabilities of using the solar energy for energy supply of the dwelling buildings of the historical area of Saint-Petersburg and for city environment quality improvement, Architecture and Modern Information Technologies, 1 (22) (2013), pp [15] D. Vuksanovic, V. Murgul, N. Vatin, E. Aronova: Shadowing impact on amount of power generated by photovoltaic modules. Applied Mechanics and Materials. Vols (2014), pp [16] A. Dodoo, L. Gustavsson, R. Sathre, Primary energy implications of ventilation heat recovery in residential buildings, Energy and Buildings, Volume 43, Issue 7, (2011), pp [17] Y.-El Fouih, P. Stabat, P. Rivière, P. Hoang, V. Archambault, Adequacy of air-to-air heat recovery ventilation system, Energy and Buildings, Volume 54, (2012), pp [18] J. Laverge, A. Janssens: Heat recovery ventilation operation traded off against natural and simple exhaust ventilation in Europe by primary energy factor, carbon dioxide emission, household consumer price and energy, Energy and Buildings, Vol. 50, (2012), pp [19] Information on 11-klima-und-lueftungstechnik?download=6:kompaktlueftungsgeraete-suprabox-comfort [20] V. Pilipenko, L. Danilevskiy, S. Terekhov, Sistemy avtomatizatsii energoeffektivnogo panelnogo zhilogo doma v Minske. Minsk, (2010), pp [21] Information on [22] Information on [23] Yu.A. Yermakov: Ventilyatsiya kvartir v tipovykh zhilykh domakh. Vodosnabzheniye i sanitarnaya tekhnika, 12, (1956). pp [24] V. Murgul: Solar energy systems in the reconstruction of heritage historical buildings of the northern towns (for example Sankt-Petersburg). Journal of Applied Engineering Science, Vol. 12 (2) (2014), pp

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