THE INSTALLATION OF THE MONTH The Palace of Nations in the city of Dushanbe in Tajikistan TAJIKISTAN Night simulation Tajikistan is one of the nations that came into being in 1991 after the disintegration of the USSR - an event that is still very much in the air and which often comes up in conversations. It marked a historic break between "now" and "then", or the "Soviet time" as most Tajiks never tire of repeating. Cotton cultivation is still the main activity on the land, and it is the determining factor in family and village life throughout the year. The government, the NGOs and the international development agencies still have a great deal to do, but the basis is already in place. One specific demonstration of how this country is developing is the contract awarded to an Italian company by the Executive Council of the President of the Republic of Tajikistan for the planning and construction of the Palace of Nations, a building of monumental dimensions in Dushanbe, the capital. Participants in the project Client: Architectural project: Structural project: Plant projects: Plant installation: Technical contract co-ordination: Executive Council of the President of the Republic of Tajikistan Codest International Udine - Italy Codest International Udine - Italy RC Impianti Udine Italy (Gruppo Busi) RC Impianti Udine Italy (Gruppo Busi) Studio Tecnico RC Impianti Without wanting to seem trite, we may claim that the Sauter brand is a valid concept when it comes to the construction of complex plants as the following account illustrates. / Palazzo delle Nazioni_Dushambe_Tajikistan_e.doc / S12 Created by Fr. Sauter AG, CH-Basel
2 / 13 Technical data for the Palace of the Republic Total roofed area: approx. 32,000 m 2 Basement level: 10,300 m 2 Floors 1, 2 and 3: 6,500 m 2 each Floor 4: 2,300 m 2 Surface area of largest halls: Ceiling height: 510 m 2 each 9 m Central atrium on floor 1: 1,450 m 2 Total volume of building: 243,000 m 3 Accessible level on floor 4: Council Chamber on floor 4: Tip of flagstaff on cupola: Length of floor heating plant: at a height of 29 m diameter 18 m, 280 seats, topped by a 16 m-high cupola 50 m above the ground floor 13,400 m The first problem to be confronted by the project developers was how to implement the wide range of functionalities for the structure so as to fulfil the various potential purposes for its use and to meet modern-day requirements. For this reason, the aim was to ensure flexible and independent operation of the HVAC systems located in the halls, state rooms and offices. Project data Outdoor thermo-hygrometric conditions Winter: Summer: Indoor thermo-hygrometric conditions Winter:- -13 C; -10.7 kj/kg 34.3 C; 5.8 kj/kg Entrance halls and stairs 16 C; 50% rh State rooms 20 C; 50% rh President's chambers 20 C; 40 50% rh Technical rooms 5 C Summer:- Entrance halls and staircases 27 C; 40 60% rh State rooms 26 C; 40 60% rh President's chambers 26 C; 40 60% rh UPS room and transformers 28 C Occupancy levels Due to the nature of usage for this building, which combines the President's residence, the most important ministries including the relevant offices, the assembly chambers for the government and all the state rooms that are typical of a centre of government, it was virtually impossible to determine a figure for maximum simultaneous occupancy levels. For this reason, the calculation was carried out on the basis of the drawings of the facility.
3 / 13 Ventilated fresh air In rooms where people are continuously present 60 m 3 /h per person Temperatures of water circuits Municipal district heating 85 65 C UTA heat exchanger circuits 80 60 C Underfloor heating plant circuits (climatic compensation) 37 32 C Circuits for ventilation convectors and radiators (climatic compensation) 70 60 C Reference specifications All the specifications that are valid within the Russian federation, in particular GOST, SNIP and MSN. All air handling units were equipped with independent control on the basis of time programming (daily or weekly), located in the DDC control centre. To enable readers to understand the difficulties that arose, and in order to meet both the architectural and the mechanical requirements, the following brief list shows the complexity of the characteristic types of usage for the mechanical plant and the safety equipment, together with a brief description of their modes of functioning. Function sequences in winter mode In 'off' mode, the situation is as follows:- Recirculated air, fresh air and exhaust air dampers closed Control valves by-pass opened (circuit) Humidification not active The following events occur when operation is started:- The circulation and extraction fan starts The dampers open The control valve for the pre-heating heat exchanger goes into operation in order to keep the temperature detected by the sensor at 20 C Humidification goes into operation, in order to keep the relative humidity measured by the sensor in the exhaust air duct at about 50% The control valve for the heat exchanger goes into operation in order to keep the temperature detected by the sensor in the exhaust air duct at 20 C (top-up heat) The control valve for the cold exchanger is in the control position according to requirements. The fan speed is controlled continuously so as to keep the pressure constant.
4 / 13 Summer mode The circulation and extraction fan starts The dampers open The control valve for the pre-heating heat exchanger is closed. The control valve for the cold exchanger operates in order to retain the following values:- The temperature measured by the sensor in the exhaust air duct at 26 C. The relative humidity measured by the sensor in the exhaust air duct at 50%rh. Humidification goes into operation in order to keep the relative humidity measured by the sensor in the exhaust air duct at 50% The control valve for the heat exchanger goes into operation in order to keep the temperature measured by the sensor in the exhaust air duct at 26 C (top-up heat). The fan speed is controlled continuously so as to keep the pressure constant. Frost-protection alarm system If the frost-protection thermostat (positioned below the pre-heating heat exchanger) is triggered, the following actions take place:- Fans: switched off Fresh air and exhaust air dampers: closed Control valve for pre-heating/top-up-heating: fully opened Humidification: not active Due to the very cold outdoor temperatures, special attention was paid to operation in winter mode, because using a frost-protection thermostat on its own would perhaps have been an inadequate solution. For this purpose, a circulating pump was installed on the pre-heating heat exchanger, allowing the water to circulate even when the valve is closed. If the pump fails, the DDC controller sends an alarm signal to the central monitoring system in order to guarantee prompt intervention by the maintenance service. Extra safety is provided by the use of a contact sensor for the temperature, positioned at the heat exchanger outlet (water side); this prevents the valve from opening if the water temperature in the heat exchanger drops below 5 C, thanks to software for this purpose included in the DDC controller programme. The two service units in the President's offices are the only ones connected to an air-conditioning system that provides for the use of different power levels (VAV), and these are also controlled via the monitoring system. These units are also supplied with centralised primary air; the VAV boxes are equipped with a power controller fitted with a dynamic p sensor. An electric heat exchanger for preheating in several stages is also installed for each VAV box. The controller on the VAV box regulates the air volume so as to keep the ambient temperature measured by a temperature sensor at constant values of 20 C in winter and 26 C in summer. The electric heat exchanger for topping up heat and the VAV box are regulated by the DDC controller, and are linked to the monitoring system via bus.
5 / 13 CENTRAL COOLING SYSTEM Cooling groups There is provision for the cooling function to be used throughout the year thanks to the installation of a four-pipe plant to distribute the cooling water. As a reduction in the power required can be assumed during the winter, only one of the two cooling groups will be in action in this season, selected according to the principle of rotation. During operation, the groups are controlled autonomously via their own control panel in order to keep the circulating water temperature at the pre-specified setpoint. Primary pumps for cold water Two of the three installed pumps are always functioning while the third serves as a reserve; during the winter, when only one of the two cooling groups is active, only one of the pumps will be functioning. Pumps for the AHU cooling circuit Pumps for the fan-coil cooling circuit One pump in each pair is intended to function continuously and the other should be in reserve, in both winter and summer modes. Only one of the double pumps is in operation, in summer and winter modes alike. The second pump is used as a reserve in change-over mode. CENTRAL HEATING UNIT Plate heat exchanger, hot water, heating The source of heat for the heating system is the municipal district-heating network which supplies water at a temperature of 85/65 C. The secondary circuit uses hot water at 80/60 C which is produced with the help of plate heat exchangers. In summer and winter alike, the system is in action 24 hours a day. The two-way valve controls the secondary circuit to 80 C. Recording the heat consumption A meter for energy consumption is installed at the district heating intake. This meter is connected to the monitoring system in order to check and register the consumption of thermal energy. Central pumps for the heating circuit Circuit pumps, heat exchangers for re-heating One of the two pumps functions in winter and summer mode alike, while the other is in standby mode. Circuit pumps, heat exchangers for pre-heating Circuit pumps, underfloor heating Circuit pumps for radiators and fan coil Circuit pumps, air movement In winter mode, one of the two pumps is always functioning and the other is in standby mode. The pumps are switched off in the summer.
6 / 13 Both periodic and automatic change-over in case of a fault is provided for all the circulation pumps via the DDC controller to which they are connected; any irregularities (such as non-function on start-up or activation of the thermal trigger) are signalled to the monitoring system so that speedy rectification of the problem is guaranteed. Temperature control for the underfloor heating circuit In winter mode, the control system is active 24 hours a day. The system is switched off in summer mode. The two-way control valve regulates the flow temperature to the predefined value, depending on the outdoor temperature, as shown in the graph in Fig. 1. T flow [ C] T outdoor [ C] Fig. 1 Graph showing the compensation of the circulation temperature for the underfloor heating; flow temperature setpoint is a function of the outdoor temperature When the safety thermostat for the maximum flow temperature operates, the valve is closed immediately, the circulation pump is disabled and an alarm is sent to the monitoring system. Temperature control for the radiator and fan coil circuit The control system is always active 24 hours a day during winter mode, and it is switched off in summer mode. Control is ensured by the two-way control valve, keeping the circulation temperature to the predefined value which is compensated according to the ambient temperature; see Fig. 2. T flow [ C] T Outdoor [ C] Fig. 2: Graph showing compensation of circulation temperature for radiators and fan coil
7 / 13 Heat and cold production The thermal carrier for the production of hot water for the heating systems is the municipal districtheating network, supplying water at a maximum temperature of 85 C with t at 20 C. Two plate heat exchangers are used to produce the temperature-controlled water; each of them has a capacity of 2200 kw and one is used only as a reserve. Control groups with two-way valves are used to produce warm water at a lower temperature, with compensation based on the outdoor temperature. Two roofed groups of air-cooled Climaveneta FOCS 3602/SLS chillers are installed outdoors to produce cooling water; these low-noise plants have highly efficient screw-shaped compressors, and each of them is designed for 66% of the maximum required load. The cooling power of each machine is 760 kw with total power of 1,100 kw. PRODUCTION OF HOT WATER FOR THE SANITARY INSTALLATIONS Plate heat exchangers The thermal source for the production of hot water for the sanitary installations is the municipal district heating network, which supplies water at a temperature of 85/65 C. The system is always active, i.e. 24 hours a day in winter and summer. The two-way control valve operates to keep the circulation temperature of the hot water for the sanitary installations at 60 C. When the safety thermostat for the maximum circulation temperature operates, the two-way valve closes immediately and sends an alarm signal to the monitoring system. Provision is made for the use of a programme to prevent legionella. Circuit pumps, exchanger-storage tank Circuit pumps for sanitary water One of the two pumps is always in operation and the other is in standby mode. Emergency in sanitary hot water production The storage tank for the sanitary hot water is equipped with three electric top-up heaters, each of 15 kw. Should it be impossible to reach the setpoint temperature at the outlet of the plate heat exchanger, the monitoring system can activate these top-up heaters to control the setpoint of 60 C as appropriate. FOUNTAINS The fountains distributed throughout the palace are operated by four pump stations. Each station is equipped with an electric command system which also handles the necessary automation functions. In this case, too, a collective alarm signal is sent to the monitoring system. Starting up and switching off each single station in the system is controlled via a daily or weekly programme.
8 / 13 COOLING UNITS FOR THE ELECTRICAL ROOMS Two autonomous split units are provided to cool these rooms, ensuring guaranteed temperatures inside the UPS and transformer rooms. The units are controlled via a system located on the machines themselves. A collective alarm signal is sent to the monitoring system, and an alarm signal for excessive temperature (supplied by an ambient thermostat one per unit) is also sent. SIGNALLING FOR SAFETY SYSTEMS, WATER OVERPRESSURE, FIREFIGHTING AND DAMPERS SAFETY SYSTEMS The monitoring system is responsible for visualising the signals from the fire detection system and the shock/impact protection system. The central fire alarm panel makes the on-off operation signals available to the dispatcher. These signals are broken down as follows:- System for automatic identification of the problem Detection of CO Operation of the sprinkler system The user can check the automatic operations linked to the event from the dispatcher and/or can perform the manual interventions required to secure the plants. The central shock/impact protection panel also sends an on-off signal to the dispatcher to indicate the overall alarm situation. WATER OVERPRESSURE ON HYDRANTS AND SPRINKLERS The central panels for overpressure on hydrants and sprinkler systems are fitted with an electrical control panel which also performs the necessary automation functions. Collective status and/or alarm signals are sent to the monitoring system from the electrical indicator panel. The maintenance staff will be responsible for checking the extent of the malfunction on the spot. DAMPERS Fire and smoke protection dampers are provided for each storey, facing the inner courtyards. If an emergency situation arises, the signals to put the dampers into the safety position are forwarded to the dispatcher. The signals are sent for each zone, and collectively for each type of damper. If a fire alarm occurs in a zone, the user checks the automatic function of the actions to protect that zone on a graphic display. The smoke protection dampers open in response to the signal from the fire detection system; they are closed manually. The fire protection dampers transmit a signal only in the closed state, and they are opened manually.
9 / 13 MONITORING OF THE ELECTRICAL SYSTEMS The monitoring system is responsible for checking the status of the main components of the MT/BT distribution and the emergency supply. This is carried out by ascertaining and visualising the current status and type of malfunction:- Circuit-breakers to protect the transformers on the MT side MT/BT transformers via the central protection panel Circuit-breakers for the incoming line and connections; AVR for the BT distribution system Generator groups UPS All the equipment that sends the monitored signals is installed in the technical zone on the basement level. The system also records the energy parameters which are transmitted by multifunctional instruments installed at both incoming points for the BT line of the general distribution system, QDG.1. The instantaneous electrical parameters are visualised for each incoming point of the line and the electrical energy is recorded. The systems installed on the general distributor panel have outputs with pulses for active and reactive energy, RS485 communication with the Modbus-RTU protocol for immediate measurements, and insulated alarm contacts. THE CONTROL AND MONITORING SYSTEM Here, too, the project developers had to decide carefully which solutions were to be selected and what approach was to be adopted for the construction of the plant and for operation of the entire plant after completion. It was decided to use a monitoring system of the latest generation in order to guarantee all the necessary automatic features, and as far as possible to limit the deployment of the maintenance staff to cases where intervention is really essential. Man-machine interaction takes place via graphic dynamised screens which optimise staff deployment time, improve the handing of maintenance operations and allow more accurate setting of parameters for ambient comfort. The monitoring system is able to integrate all the multiple functions needed to manage the plants under its supervision and, if necessary, it can interact with the other units that make up the overall architecture (Fig. 3); thanks to its hardware and software components, this system allows control, supervision and maintenance of the monitored plants with maximum efficiency.
10 / 13 Fig. 3 The following plants are monitored and/or controlled in this project:- Production and distribution of fluids Air-conditioning Heating Electrics Safety systems Integration of all the operating functions for the individual plants in the system optimises the use of energy and human resources by eliminating all the manual operations that take a large amount of the staff's working time (readings, checks, activations, measurements, etc.). In this way, the proposed system allows real-time monitoring of error-free functioning throughout the building by one or more employees, with the help of graphic operating stations or portable terminals. When the system was being developed, special attention was paid to the end users and the maintenance staff. The main problem was to produce a simple and intuitive graphic plant interface in schematic form, in two languages English and Russian. For this purpose, the entire building was accurately mapped (right down to the foundations) so as to allow users to navigate easily between the various parts of the palace. As shown in Figs. 4 and 5, users can access the various plants intuitively by selecting the floor containing the locations and reference points for the air-conditioning units and the special plant.
11 / 13 Fig. 4 Fig. 5
12 / 13 For the monitoring of the individual air-handling units, the structure of the machine as well as the relevant reference points such as sensors and triggers were accurately mapped. This makes it easy for the maintenance staff to interpret the visualised information on the graphic screen (Fig. 6). Fig. 6 Information boxes are shown for the electrical and safety systems. These boxes use dynamic displays to indicate the status of the switches, alarm statuses and electrical variables (Fig. 7). Fig. 7 Fig. 7
13 / 13 Company brand names Cooling groups: Heat exchangers with plates: Air-handling units: Extraction fans: Convectors: Base plates: Air distribution ducts: Distribution diffusers: Spiral diffusers: Pumps: Building automation: Water treatment: CLIMAVENETA FIORINI COVENCO INTERNATIONAL FRANCE AIR TRANE RDZ P3 Ductal FRANCE AIR FRANCE AIR DAB SAUTER CULLIGAN Our thanks go to Mr Sandro Mansutti of R.C. Impianti (Udine) for his co-operation. He supplied the technical documentation for this article.