Design & Product Guide. Danfoss FlatStations.

Transcription

1 Design & Product Guide Danfoss FlatStations Rev: /2015

2 About SAV Systems SAV has been operating in the UK since SAV Systems is a leading provider of innovative building services solutions designed to boost energy efficiency and cut carbon emissions. Products vary from sophisticated mini-chp systems to simple water meters, but all are purpose-developed to serve a better internal environment and a greener world. Used as individual products, or integrated into custom-designed systems, the SAV range makes a perfect partner for low energy technologies from renewables to central plant and even district heating systems. It s a full family of choice sourced from some of the world s leading specialist companies - our Partners in Technology. Product groups cover the full spectrum of modern building services. UK CUSTOMER SUPPORT CENTRE SAV Systems, Scandia House, Boundary Road, Woking, Surrey GU21 5BX Telephone: +44 (0) info@sav-systems.com GENERAL INFORMATION: Office Hours: 9.00am pm Monday to Friday.

3 FLATSTATION DESIGN GUIDE Contents Design Guide 1. INTRODUCTION CLIENT BENEFITS DELTA T DESIGN FLATSTATION SELECTION SYSTEM LAYOUT Primary circuit and buffer vessel (A) Mains cold water supply (B) Secondary pump (C) Differential pressure sensor (D) Top of riser (E) Flushing and commissioning provisions (F) zone compliance kit (G) Heating circuit balancing SYSTEM SIZING Module selection District heating pipe sizes Sizing of heat source Buffer tank sizing Sizing example METERING COMMISSIONING Pre-commissioning checks Flow balancing in district heating circuits and radiator circuits Capacity testing individual FlatStations Capacity testing - district heating system Specification...18 Product Guide Danfoss FlatStations - 1 Series BS...20 Danfoss FlatStations - 1 Series DS Fully Insulated...21 Danfoss FlatStations - 3 Series BS...22 Danfoss FlatStations - 3 Series BS Basic...23 Danfoss FlatStations - 3 Series BS Basic Fully Insulated...24 Danfoss FlatStations - 4 Series Cooling...25 Danfoss FlatStations - 5 Series BS...26 Danfoss FlatStations - 5 Series DS Fully Insulated...27 Danfoss FlatStations - 7 Series BS...28 Danfoss FlatStations - 7 Series DS Fully Insulated...29 Danfoss FlatStations - 7 Series BS Dual Heat Source...30 Zooming in Danfoss IHPT - Self-acting DHW Controller...32 Danfoss AVTB - Self-acting DHW Controller...34 Danfoss RAVK - Self-acting Heating Circuit Controller...36 Danfoss AVPL - Self-acting Differential Pressure Controller...37 Danfoss Sonometer Ultrasonic Compact Energy Meter...38 Izar Center - M-Bus Master...39 Micro Plate Heat Exchanger (MPHE)

4 FLATSTATION DESIGN GUIDE 1. INTRODUCTION This guide explains how to design and commission heating systems for apartment blocks and district heating schemes incorporating Danfoss FlatStations. These are heat interface units (HIUs) that incorporate plate heat exchangers for transferring heat from a piped distribution main to localised heating and hot water systems. Danfoss FlatStations significantly outperform alternative products due to their patented valve technology and energy saving features, including: specialised valves for accurate control of hot water pressure and temperature energy efficient primed temperature set-back function for periods of zero demand thermally insulated casings to minimise heat losses. To maximise the energy saving benefits of the units, proper system design is essential. This guide provides recommendations for: unit sizing heating system layout integration of low carbon heat sources prediction of hot water simultaneous demands Please also see CHP Design Guide for considerations related to CHP and plant room design specifically and Delta T Design Guide for considerations regarding optimization of system delta t. 2. CLIENT BENEFITS For client organisations, the particular benefits of Danfoss FlatStations are as follows: Minimal space requirement Danfoss FlatStations are provided in compact, well designed, casings. They therefore take up far less room than an equivalent thermal store or an equal capacity combi-boiler. Low maintenance Unlike combi-boilers, Danfoss FlatStations do not require extensive servicing and maintenance. Easy to incorporate individual metering and billing services In a sub-tenanted apartment block that requires separate metering and billing of energy used, Danfoss FlatStations can be integrated with intelligent heat metering that automatically monitors and records energy consumption and enables automatic billing of tenants based on energy used. Experience shows that individual billing, based on actual consumption, also leads to behavioral changes resulting in lower consumption and reduced energy costs. Improved SAP ratings - The SAP rating achievable by using Danfoss FlatStations in dwellings, fed from a community heating system with low carbon heat source, will be significantly better than for systems with distributed combi-boilers or hot water cylinders. This will also help to achieve target ratings under the Code for Sustainable Homes. Ease of integrating with low or zero carbon technologies The centralisation of the heat source, and inclusion of a thermal store, makes it easier to incorporate a low or zero carbon technology such as combined heat and power (CHP), solar thermal or biomass boilers. Improved efficiency of heat sources Danfoss FlatStations enable low heating return water temperatures which are crucial to maximising the energy efficiency of heat sources such as combined heat and power, or gas fired condensing boilers. It is recommended that the return water temperature from a community heating scheme should not exceed 25 C for hot water systems and 40 C for radiator systems. During hot water generation, Danfoss FlatStations typically return heating water around 20 C easily complying with the recommendations. 4

5 FLATSTATION DESIGN GUIDE Minimised risk of legionella Because there is no stored hot water the risk of legionella bacteria multiplying in the system is minimised. Thermostatic temperature control Danfoss FlatStations provide thermostatic control of hot water temperature at varying inlet pressures. Hence, hot water can be supplied at whatever temperature setting is required, and this temperature is unaffected by the subsequent opening or closing of additional taps off the same system. Low heat losses from casings Danfoss FlatStations can be provided in thermally insulated casings in order to minimise the uncontrolled loss of heat. This ensures that all of the heat delivered to each apartment is used for useful heat production and that there are no uncontrolled heat emissions during summer months. Lower energy bills Correct system design and high efficiency FlatStations ensures energy bills are kept to a minimum. 3. DELTA T DESIGN District and community heating systems utilising low carbon heat sources (such as condensing boilers, biomass boilers, CHP units, heat pumps, etc.) should be designed to achieve the lowest possible flow temperature and the maximum possible flow to return temperature differential (i.e. delta T). This will enable low carbon heat sources to operate more efficiently and for longer periods whilst minimizing pipe sizes, pipe emissions and thermal store volumes. Full details of delta T design is provided in the SAV Delta T design guide. In order to maximize secondary circuit delta T values, terminal units must be able to dissipate as much heat as possible from the circulating water. For hot water production, heat interface units have been specifically designed with this in mind. Early heat exchanger plate (source: Danfoss) When the benefits of delta T design were first realized, manufacturers set about designing high efficiency heat exchangers, capable of very high rates of heat transfer but with manageable dimensions. This led to the development of plate heat exchangers that are now a critical component of heat interface units. Heat interface units incorporate plate heat exchangers to transfer heat from the heating distribution system to hot water for use at taps. Heating water entering at up to 70 C can be cooled to temperatures in the range C as it by heats incoming cold water. Heat interface units are essential for the operation of many district and community heating systems, as reflected in the latest industry guidance. For example, CIBSE s AM12/2013 Combined heat and power for buildings section 9.16, Design of district heating states: It is recommended that, for new systems, radiator circuit temperatures of 70 C (flow) and 40 C (return) are used with a maximum return temperature of 25 C from instantaneous domestic hot water heat exchangers. Furthermore, Greater London Authority s District Heating Manual for London (2013) specifically recommends that return temperatures from hot water generating heat interface units do not exceed 25 C. These requirements make hot water cylinders unacceptable since, due to the legionella risk associated with hot water storage, return temperatures have to be kept above 60 C. The only feasible solution is the utilisation of heat interface units such as Danfoss FlatStations. These units incorporate accurate temperature and pressure control valves that ensure uninterrupted hot water supplies and consistently low system return temperatures. For further guidance, please also refer to Heat Networks: Code of Practice for the UK by ADE/CIBSE. 5

6 FLATSTATION DESIGN GUIDE 4. FLATSTATION SELECTION The appropriate Danfoss FlatStation is the one that can meet the anticipated kw heating and hot water requirements for the project at the design district heating circuit operating temperatures. Each FlatStation has a specific product datasheet which gives sizing examples based on different district heating operating temperatures. Heating demand The estimation of heat losses and consequent heating loads for dwellings is explained in BS EN 12831:2003 Heating Systems in Buildings Method for calculation of the design heat load. Similar advice is provided in the CIBSE Domestic Heating Design Guide. Peak heating demands should be calculated based on this guidance. Hot water demand The peak simultaneous demand from the hot water outlets to be served by the FlatStation must be estimated. For many system designers BS 6700 used to be the usual source of simultaneous demand values for multiple fittings. However, in 2012 BS 6700 was superseded by BS 8558 together with BS EN 806 part 1-5 as the new standard for DHW systems. The current standard states the designer is free to use a nationally approved detailed calculation method for pipe sizing, such as the Danish Standard DS 439, which is also the standard recommended in CIBSE AM12:2013. Section 6 System sizing of this Design Guide will show how to apply the Danish Standard DS

7 FLATSTATION DESIGN GUIDE 5. SYSTEM LAYOUT A typical layout for a complete heating and hot water system incorporating Danfoss FlatStations is shown below. Some valves have been omitted for clarity. G FLATSTATION E HTG F&R H&CW HTG F&R H&CW F P D HTG F&R H&CW A PRIMARY CIRCUIT C B BOOSTED MCW The following sections 5.1 to 5.8 describe the main design issues which need to be considered to ensure effective and efficient performance of both heating and hot water supplies. 7

8 FLATSTATION DESIGN GUIDE 5.1 Primary circuit and buffer vessel (A) The primary circuit should incorporate heat sources (such as boilers, CHP units etc) with primary pumps sized to circulate water to a low loss header. The circuit should be planned and sized in accordance with the advice provided in the SAV Delta T design guide. It is essential that the primary circuit includes a suitably sized buffer vessel. It may be the case that a buffer vessel is required to improve the performance of low carbon heat sources such as CHP units and biomass boilers, enabling them to run for longer periods. However, a buffer vessel is also essential for the operation of any system serving Flatstations since it serves as an energy store, catering for high but short term hot water demands. Without a buffer store, the central heat sources may be unable to react with sufficient speed to the load imposed by high but temporary hot water demands. The buffer tank should be dimensioned such that temperature stratification is encouraged. Hence, an elongated vertical cylinder is appropriate with primary and secondary flow pipes located near the top of the tank, whilst primary and secondary return pipes are located near the bottom. The secondary return temperature should be maintained at as low a value as possible. Temperature sensors located in the side of the vessel can be used for on/off sequencing of multiple heat sources, as described in the SAV Delta T design guide. 5.2 Mains cold water supply (B) A minimum mains cold water supply of at least 0.5 bar is required for the BS range of FlatStations whereas a minimum pressure of 1.0 bar is required for the DS range of FlatStations. However, the actual pressure provided should also depend on the requirements of the hot water outlets fittings which may require higher pressures to operate correctly. In tall buildings the required cold water pressure will typically be achieved by provision of a boosted main with pressure reducing valves set to the required pressure on each floor branch. 5.3 Secondary pump (C) The secondary pump should be variable speed to take advantage of pump energy savings when the heating system is operating at part load. Pump speed should be controlled such that there is always sufficient pressure available to satisfy the most remote Danfoss FlatStation. The heating side pressure loss value for each Danfoss FlatStation is provided in the appropriate product brochure. 5.4 Differential pressure sensor (D) A differential pressure sensor installed across the most remote Danfoss FlatStation will minimise pump energy consumption. Pump speed should be controlled to maintain the required minimum pressure differential across the most remote FlatStation. 5.5 Top of riser (E) The ADE/CIBSE Heat Networks: Code of Practice for the UK (draft version at time of print) states in its minimum requirements: where bypasses are required to maintain flow temperatures above a minimum level at times of low demand, temperature controlled bypass valves are preferred. Where fixed bypasses are used, the flow rate shall be limited by means of a differential pressure control valve and regulating valve to no more than 1% of peak demand flow at all times, unless a detailed calculation shows that a higher rate will be required. In residential schemes the standby flow rate through instantaneous hot water heat exchangers will normally be sufficient to maintain the flow temperatures without the need for other bypasses ( ) the use of bypasses shall be minimised - where instantaneous heat 8

9 FLATSTATION DESIGN GUIDE exchangers are used, the standby flow will normally result in a sufficient bypass flow. Fixed bypasses shall not be used and any bypasses shall be temperature controlled so that the bypass only operates when flow temperatures are below a minimum set point As described later in this guide, the Danfoss FlatStations include a primed DHW function, allowing a small by-pass as referred to above. If no system by-pass is installed at the top of the riser a valve should be in place which can be opened for system flushing. It is important for any system that there are no system by-passes allowing excessive flows of un-cooled water back to the central plan compromising the system return temperature. 5.6 Flushing and commissioning provisions (F) The features shown are as recommended in BSRIA Application Guide BG29/2012 Pre-commission Cleaning of Pipework Systems. Each FlatStation should be treated as a terminal unit fed from the main heating system pipework. In accordance with the BSRIA guide, SAV provide all FlatStations with their own flushing by-pass and flushing drain cock. The flushing by-pass will enable the main system pipework to be flushed and cleaned whilst the FlatStation remains isolated. The drain cock will enable the FlatStation to be flushed if required. These provisions should protect the heating water side of each unit but it is also possible that debris could be carried into the plate heat exchanger with the incoming mains cold water. It may therefore also be prudent to install a strainer on the mains cold water supply to the heat exchanger in areas where water is known to contain some level of suspended solids. Pressure test points are required to facilitate commissioning. Each module requires a minimum pressure differential across it in order to function correctly. Pressure tappings across the primary heating circuit flow and return pipes will enable the available pressure to be measured and confirmed as adequate zone compliance kit (G) The 2010 edition of the Domestic Building Services Compliance Guide requires that new dwellings are divided into at least 2 heating zones, each with programmable room thermostats connected to actuators in the pipes serving each zone. This can be achieved using SAV s 2 zone compliance kit which comprises a two port manifold with integral zone valves, actuators and wiring box. Programmable room thermostats can be added for full temperature and time control. 5.8 Heating circuit balancing System return temperatures and consequently system efficiencies will inevitably depend on heating circuit return temperatures secondary side of the heat interface unit. This is the reason underfloor heating works so well with central plant systems, as they operate at low temperatures and thereby contribute to low system return temperatures. In any system heating circuit balancing is paramount. For radiator circuits a single uncontrolled radiator or towel rail can jeopardise the system efficiency. It is therefore crucial that heat emitters are both balanced and specified with the right controls. Specifying pre-settable TRVs with variable Kv values at design stage will help achieve low system return temperatures in practice as lockshield valves are very seldom balanced correctly on site. Pre-settable TRVs will allow the site engineer to simply pre-set each valve relative to the heat output from the radiator schedule and leave the lockshield valve fully open. 9

10 FLATSTATION DESIGN GUIDE 6. SYSTEM SIZING 6.1 Module selection As discussed in section 4, individual FlatStations must be selected based on an assessment of the maximum heating demand and maximum simultaneous hot water demand for each dwelling under consideration. It is also necessary to know the intended operating temperatures for the district heating system. 6.2 District heating pipe sizes Each district heating system pipe must be sized to accommodate the maximum heating and hot water demands of the FlatStations served by that pipe. The maximum heating demand is relatively predictable, this being the summation of the calculated heating loads for each of the dwellings served. However, the estimation of maximum hot water demand is less obvious. It is extremely unlikely that all of the hot water taps in all of the dwellings served will be open simultaneously. Therefore, some allowance for the diversity in usage is required. The degree of diversity for multiple dwellings is expressed as a coincidence factor and is defined as: (1) Where F = coincidence factor DFR = design flow rate for downstream hot water outlets (l/s) MFR = maximum possible flow rate for downstream hot water outlets (l/s) The diversity factors recommended for sizing supplies to multiple dwellings by CIBSE AM12:2013 are shown in the graph opposite. 10

11 FLATSTATION DESIGN GUIDE 1 Coincidence factor for DHW Coincidence factor Danish Standard DS Number of dwellings NOTE: The Danish Standard DS 439 calculation method has been approved in BS 8558/BS EN stating the designer is free to use a nationally approved detailed calculation method for pipe sizing. Furthermore CIBSE AM12:2013 states: Experience from continental schemes indicates that the BS 6700 (BSI, 2009a) factors are too conservative and Danish Standard DS 439: 2009 (Dansk Standard, 2009) diversity factors are recommended for sizing supplies to multiple dwellings. Other guidance, such as A technical guide to district heating (BRE, 2014) and the Heat Networks: Code of Practice for the UK (ADE/CIBSE, draft at time of print) likewise advocate the use of the Danish Standard DS 439 for application of an appropriate coincidence/diversity factor. Calculation of flow rates for pipe sizing Using the appropriate coincidence factors estimated from the above graph, the maximum design flow rate for each section of heating pipe can be determined. The flow rate for each pipe must be capable of delivering the peak heating demand for the dwellings served by the pipe, plus the peak simultaneous hot water heating demand for those dwellings. The overall design flow rate for each section of pipe will be: Q T = (FQ DHW )+(Q HTG ) (2) Where, Q T = total design flow rate in district heating pipe (l/s) F = coincidence factor Q DHW = heating water flow rate required to meet peak domestic hot water demand (l/s) Q HTG = heating water flow rate required to meet peak heating demand (l/s). 11

12 FLATSTATION DESIGN GUIDE The value Q DHW can be calculated from the equation: Q DHW = P DHW 4.2 x ΔT DH (3) Where, P DHW = power requirement (kw) for all downstream FlatStation hot water heaters T DH = design temperature drop across the district heating side of the heat exchanger during hot water production (typically around 60 C, i.e. 80 C in, 20 C out).the value Q HTG can be calculated from the equation: Q HTG = P HTG 4.2 x ΔT HTG (4) Where, P HTG = power requirement (kw) for all downstream apartments (typically 3-10kW each) T HTG = design temperature drop across the district heating system (typically C). 6.3 Sizing of heat source There is no necessity for the power output of the central heat source to match the calculated peak heating and hot water demand from the district heating system. This is because the peak demand should only occur for relatively short periods, this being when all heating systems are on and there is peak hot water draw-off. This condition is unlikely to be sustained for a prolonged period. On this basis, two factors enable the heat source capacity to be reduced: When there is a draw-off of hot water, each FlatStation prioritises the hot water circuit, temporarily reducing the flow of water to the heating circuit. Since hot water demand periods are relatively short, this does not affect internal temperatures. A central buffer tank (see sections 5.1 and 6.4) provides a thermal store to enable the system to cope with large but short term hot water demands. The store empties during peak demand and then re-fills when the demand has passed. Hence, the heat source power capacity can be sized such that it is sufficient to cope with the entire heating load (P HTG ), plus an additional allowance sufficient to re-heat the volume of water in the buffer tank within 1 hour (P BUFFER ). 12

13 FLATSTATION DESIGN GUIDE The power required to heat the contents of the buffer tank within 1 hour can be calculated from the equation: P BUFFER = V x 4.2 x ΔT HTG 3600 Where, V = heated (and hence useful) volume of buffer tank 6.4 Buffer tank sizing The buffer tank should be sized to deal with the anticipated peak heating and hot water demand sustained over a notional period of 10 minutes (i.e. 600 seconds). Assuming that the boiler is controlled to maintain the required heating flow temperature at a point two thirds of the way down the tank, then the tank will need to accommodate 900 seconds of flow. Hence the equation for sizing the tank is as follows: V = 900FQ DHW Where, V = tank volume (litres). 6.5 Sizing example System design for a development comprising 40 identical 2 bedroom apartments, each with the following appliances requiring hot water: basin, sink, shower, washing machine, and each with a heating load of 5kW. 7 Series FlatStations are required and are to be fed from a district heating system with a designed primary flow temperature of 70 C. Solution FlatStation selection: Feeding one bath and one shower at the same time requires a mass flow rate of ~0.37 kg/s of water at 50 C, using a design temperature differential of 40K (10 C 50 C), secondary side of the plate heat exchanger. The power required to heat this volume of water to the required flow temperature (i.e. Q DHW ) is ~60kW per FlatStation. Therefore this unit should just meet the requirements of each apartment. 13

14 FLATSTATION DESIGN GUIDE Pipe sizing Each pipe must be sized individually. For the main pipe from the secondary pumps serving all 40 apartments the procedure is as follows: From the graph in section 6.2 above (accepting the DS 439 values) the coincidence factor F can be determined as From equation (2) the total flow rate for the pipe can be calculated as: Q T = (0.12 x Q DHW ) + (Q HTG ) Given a design temperature drop of 49K (i.e. from 70 C to 21 C) across the primary side of the DHW heat exchanger, Q DHW = (60kW x 40 apartments) / (4.2 x 49K) = l/s Assuming a 20K temperature drop (i.e. from 70 C to 50 C) across the primary side of the heating plate heat exchanger, Q HTG = (5kW x 40 apartments) / (4.2 x 20K) = 2.38 l/s Hence, Q T = (0.12 x 11.66) + (2.38) = 3.78 l/s Buffer tank The buffer tank volume will be: 900 x 0.12 x = 1259 litres Heat source sizing The heat source must be sized to meet the peak heating load plus sufficient power to re-heat the hot water buffer contents in 1 hour, i.e. (40 apartments x 5kW) + (1259 x 4.2 x 40K)/3600 = 259kW 14

15 FLATSTATION DESIGN GUIDE 7 METERING A metering and billing strategy should be developed for any multi occupancy scheme and it is therefore important that the FlatStations installed are equipped with an approved energy meter. The addition of an energy meter coupled with a data collection system allows the accurate monitoring and recording of the energy used to provide the heating and hot water or cooling. This data can then be used to for billing purposes. Danfoss FlatStations can be supplied with an MID class 2 and 3 approved ultrasonic energy meter. The energy meter can be fully integrated into an AMR system with data transfer through a fixed wire. Automatic Meter Reading (AMR) To future-proof the metering and billing system hardware and software installed should be in an open protocol format allowing choice of service provider. This can be specified separate to a propriety billing system, e.g. by specifying two Mbus cards in the energy meter (one for an open protocol datalogger and the other for the propriety billing system). This will ensure peace of mind for the client, even if there should be a future fall out with the billing provider. Two common AMR system options are: 1. Hard-wired Mbus metering system 2. Radio/Mbus hybrid metering system Hard-wired Mbus metering system Radio/Mbus hybrid metering system 15

16 FLATSTATION DESIGN GUIDE Hardwired Mbus (European Standard EN 13757): Mbus is the most widely used protocol and was specifically developed for the reading of heat and other utility meters being flexible and ideal for expansion with additional meters and monitoring software added as required. Radio/MBus hybrid: This is a combination of radio meters transmitting to receivers hard wired back to a central data logger. Can be very useful in challenging buildings i.e. refurbishment projects. ADE/CIBSE s Heat Networks: Code of Practice for the UK (draft version at time of print) states Direct data readings should be obtained using M-bus communications or other proven AMR technology. Heat meters that provide data via pulsed outputs are not normally recommended for use with AMR systems. Credit or Pre-Payment Credit billing is presently the most widely used, however there are a number of advantages with a prepayment system. For the client or landlord one of the most obvious advantages is the elimination of debt risk, as residents are paying for their energy in advance. The energy meter should be mains powered if a prepayment system is chosen. As a prepayment unit would connect to the energy meter at much shorter intervals than a standard datalogger it might otherwise rapidly drain the battery of the energy meter. FlatStations can be specified as prepayment ready with the inclusion of an integrated shut off valve which is suitable for connection to proprietary prepayment systems. 16

17 FLATSTATION DESIGN GUIDE 8. COMMISSIONING 8.1 Pre-commissioning checks Before system commissioning commences an inspection should be undertaken to ensure that: the pipework installation is complete, and all components are correctly positioned, correctly installed, easily accessible, properly identified (NB: refer to CIBSE Code W: 2010 Water distribution systems for more comprehensive and detailed installation check-lists) the system has been filled, thoroughly vented and pressure tested in accordance with HVCA TM6 Pressure Testing of Pipework. the system has been flushed and chemically cleaned in accordance with BSRIA Guide BG29/2011 Pre-commission Cleaning of Water Systems. the pumps and associated variable speed drives are installed, inspected and tested in accordance with the manufacturer s instructions and are ready to operate. a closed head pump test has been carried out on each pump and the results plotted on the manufacturer s pump performance graph. 8.2 Flow balancing in district heating circuits and radiator circuits Each FlatStation serving either a direct or indirect fed heating system, is fitted with its own differential pressure control valve (DPCV). These DPCVs are pre-set to maintain a fixed pressure differential across the heating circuit (if direct fed) or the plate heat exchanger (if indirect fed). The distribution circuit pumps should be controlled to vary their speed such that the pressure differential across the most remote FlatStation is maintained at a value that is sufficient to operate the DPCV in that FlatStation. (Hence, the recommendation to locate a differential pressure sensor close to the most remote FlatStation for pump speed control, as explained in section 5.4) If there is sufficient pressure differential across the most remote FlatStation, then all other DPCVs located in FlatStations closer to the pump will also be satisfied. The DPCVs will then effectively balance the flows throughout the system, allowing sufficient flow to pass through when radiators are calling for heat, but closing when room temperatures are satisfied and thermostatic radiator valves begin to close. There will be no need to proportionally balance the flows in the district heating system branches feeding to the FlatStations. The only balancing required will be between radiator branches in the heating circuits fed from each FlatStation. As described in section 5.8 radiators should be balanced by setting the pre-settable TRVs according to the heat output of the radiator schedule. (If pre-settable TRVs are not available the radiator circuit would need to be balanced by means of a temperature balance whereby the lockshield valves are regulated until the return temperature from each radiator is at approximately the same temperature.) 17

18 FLATSTATION DESIGN GUIDE 8.3 Capacity testing individual FlatStations Having established adequate temperature, flow and pressure conditions in the main heating system, the hot water outputs from individual FlatStations can be adjusted and tested as required: 1. Set the pressure reducing valves on the boosted mains water supply branches to the required value for each apartment (i.e. typically 3bar minimum such that there is sufficient pressure available to satisfy the FlatStation and downstream hot water outlets). 2. In each apartment (or selected representative apartments) open sufficient tap outlets to simulate the anticipated peak simultaneous hot water demand for the dwelling. 3. Measure the hot water temperature from the tap outlets to ensure that the temperature obtained is within expected limits, and that flow rate (and hence pressure) is adequate. 8.4 Capacity testing - district heating system In setting up the pump, it should be possible to establish maximum and minimum load operating conditions for the pump. This test should demonstrate a significant reduction in pump speed at minimum load conditions. With the system operating at its design temperature, the procedure for carrying out these tests is as follows: 1. Ensure that all radiator circuits are set to full flow i.e. all zone control valves, and radiator valves are fully open. 2. Open a sufficient number of tap outlets, starting with the most remote outlets and working back towards the pump, until the measured flow rate through the pump is equal to the calculated maximum load flow rate for the system (as calculated following the guidance in section 6.2). 3. Measure the differential pressure being generated by the pump by reference to inlet and outlet pressure gauges. Confirm and record the total flow rate leaving the pump using the flow measurement device installed on the secondary circuit main return pipe. 4. Record how long it takes to empty the buffer tank at this condition. This should be a minimum of 10 minutes. 5. Next, close all tap outlets. Override the controls to force all 2 port heating zone control valves into their fully closed positions. 6. Measure the differential pressure being generated by the pump as before, and re-measure the total flow rate leaving the pump. If the pump is being controlled properly, the pump pressure value should be close to the controlled value at the differential pressure sensor. Furthermore the flow rate should be close to the flow rate passing through the by-pass at the top of the riser. 9. Specification Please contact SAV Systems for further information and specification templates. 18

19 tried and tested globally Product Guide hydraulic balancing fast closing times minimal service requirements 19

20 FLATSTATION PRODUCT GUIDE Danfoss FlatStations - 1 Series BS Self-acting instantaneous DHW only FlatStation Circuit diagram - example DH TP 1 supply DH return TP 62B 1 DHW CVM 1 Series BS B Plate heat exchanger DHW 1 Ball valve 7 Thermostatic valve 62B Pressure Absorber Technical parameters: Nominal pressure: PN 16 DH supply temperature: T max = 120 C DCW static pressure: p min = 0,5 bar Brazing material (HEX): Copper Weight incl. cover: Cover: Dimensions (mm): Without cover: H 428 x W 312 x D 155 H 468 x W 312 x D kg (incl. packing) Grey-lacquered steel sheet (One-1;One-2) (One-3) With cover: H 430 x W 315 x D 165 H 470 x W 315 x D 165 Connections: 1 Domestic cold water (DCW) 2 Domestic hot water (DHW) 3 District heating (DH) supply 4 District heating (DH) return Seen from above (One-1;One-2) (One-3) Wall Connections sizes: DH + DCW + DHW: G ¾ (ext. thread) Options: Booster pump (increases DH flow) Safety valve DHW recirculation pump DHW: Capacity examples, 10 C/50 C FlatStation type One DHW capacity [kw] Supply flow Primary Return flow Primary Pressure loss Primary [kpa] DHW tap load [l/m] One One One Higher capacities available on demand 20

21 FLATSTATION PRODUCT GUIDE Danfoss FlatStations - 1 Series DS Fully Insulated Self-acting instantaneous DHW only FlatStation DHW 1 TP DH supply B 72 B Water heater 1 Ball valve 9 Strainer 62B Pressure Absorber 72 IHPT CWM 1 62B 9 TP DH return Technical parameters: Connections: Connections sizes: max min 3 District heating supply (DH) 4 District heating return (DH) Options: Weight incl. cover: Cover: Dimensions (mm): (incl. packing) Grey full-insulation DHW recirculation pump With metal cover: Seen from above DHW: Capacity examples FlatStation type Novi [kw] Supply flow Primary [ºC] Return flow Primary [ºC] [ºC] Pressure loss Primary [kpa] tap load [l/m] Novi-FI-1 Novi-FI-2 40,3 22, ,

22 FLATSTATION PRODUCT GUIDE Danfoss FlatStations - 3 Series BS Self-acting indirect heating and cylinder feed FlatStation Circuit diagram - example A Heat exchanger M Electrical wiring box 2 Single check valve 4 Safety valve 7 Thermostatic valve 9 Strainer 10 Circulation pump 14 Sensor pocket, energy meter 18 Thermometer 20 Filling/drain valve 21 To be ordered separately 24 Delivered loose with unit 26 Manometer 31 Differential pressure controller 38 Expansion tank 41 Fitting piece, energy meter 48 Air escape, manual 69 On/off valve 1 Cylinder supply DH supply 1 1 HE supply DH return 1 1 Cylinder return HE return Border of delivery Technical parameters: Nominal pressure: PN 10* DH supply temperature: T max = 120 C Brazing material (HEX): Copper * PN 16 versions are available on enquiry Weight incl. cover: 25 kg (incl. packing) Connections sizes: DH + HE: Options: Room thermostat Pipe insulation G ¾ (int. thread) Cover: Dimensions (mm): Without cover: H 750 x W 525 x D 330 With cover: H 800 x W 540 x D 430 White-lacquered steel sheet Connections: 1 Cylinder supply 2 Heating (HE) + cylinder common return 3 District heating (DH) return 4 District heating (DH) supply 5 Heating (HE) supply Heating: Capacity examples Heating: Capacity examples Heating circuit Heating circuit Pressure loss Flow rate Residual Heating Capacity FlatStation type Heating Supply flow Primary Return flow Heating Secondary Flow rate PrimaryMin. diff. pressure SecondaryFlow rate pump Residual head pump head FlatStation type [kw] capacity Primary Primary circuit Primary [kpa] Primary* [l/m] Secondary [kpa] Secondary VX-Z [kw] 15 80/53 50/70 (l/m) 50 [kpa] 10.7 [l/m] 12 [kpa] VX-Z / /65 40/ VX-Z / /50 65/ / /40 50/ VX-Z / /65 40/ VX-Z / /50 65/ / /40 50/ VX-Z / /65 40/ VX-Z / /50 65/ Higher capacities available on demand / Higher capacities available on demand. *Energy meter not included. 22

23 FLATSTATION PRODUCT GUIDE Danfoss FlatStations - 3 Series BS Basic Self-acting indirect heating only FlatStation Circuit diagram - example Electrical Wiring Box M DH return 4 48 Heat M 69 7 exchanger HE return DH supply bar HE supply A 1 Ball valve 4 Safety valve 7 Thermostatic valve 9 Strainer 10 Circulator pump 14 Sensor pocket, energymeter 18 Thermometer 20 Filling/drain valve 24 Deliveredloose with unit 26 Manometer 31 Differentialpressure controller 38 Expansion tank 41 Fitting piece energy meter 48 Air escape, manuel 69 On/off valve Technical parameters: Nominal pressure: PN 10* DH supply temperature: T max = 120 C Brazing material (HEX): Copper * PN 16 versions are available on enquiry Weight incl. cover: Cover: 30 kg (incl. packing) White-lacquered steel sheet Heating: Capacity examples Connections: 1 District heating (DH) supply 2 District heating (DH) return 3 Heating (HE) supply 4 Heating (HE) return Dimensions (mm): Without cover: H 750 x W 500 x D 360 With cover: H 800 x W 540 x D 430 Non-standard sizes available on request Connections sizes: DH + HE: Options: Separate mixing circuit Room thermostat Pipe insulation G ¾ (int. thread) FlatStation type VX Heating capacity [kw] Supply flow Primary Return flow Primary Heating circuit Flow rate Primary (l/m) Min. diff. pressure Primary* [kpa] Flow rate Secondary [l/m] Residual pump head Secondary [kpa] / VX / / / / VX / / / / VX / / / Higher capacities available on demand. *Energy meter not included. 23

24 FLATSTATION PRODUCT GUIDE Danfoss FlatStations - 3 Series BS Basic Fully Insulated Self-acting indirect heating only FlatStation Circuit diagram - example DH supply DH return A Heat exchanger HE M Electrical wiring box 4 Safety valve 7 Thermostatic valve 9 Strainer 10 Circulation pump 14 Sensor pocket, energy meter 18 Thermometer 20 Filling / drain valve 24 Delivered loose with unit 26 Pressure gauge Expansion tank 41 Fitting piece, energy meter 48 Air vent, manual 69 On / HE Supply HE Return Technical parameters: Nominal pressure: PN 10* DH supply temperature: T max = 120 C Brazing material (HEX): Copper *PN 16 versions are available on enquiry Weight: 30 kg (incl. packing) Insulation: Anthracite grey EPP Dimensions (mm): With insulation: H 765 W 530 D 375 Connections sizes: DH + HE: G ¾ (int. thread) Options: Possibility for electronic controller, weather compensation Room thermostat Safety thermostat, surface type on UFH units Connections: 1 District heating (DH) supply 2 District heating (DH) return 3 Heating (HE) supply 4 Heating (HE) return Heating: Capacity examples Heating: Capacity examples Heating Supply flow Return flow Heating Flow rate Min. diff. pressure Flow rate Residual pump head FlatStation type capacity Primary Primary circuit Primary Primary* Secondary Residual Secondary VX-FI pump FlatStation Heating Supply flow Heating Pressure loss Pressure loss Flow rate Flow rate [kw] (l/m) [kpa] [l/m] pressure [kpa] type capacity primary circuit primary secondary primary secondary / secondary35 [kw] [kpa] [kpa] [l/m] [l/m] [kpa] / VX-FI / / VX-1-FI / / / / / VX-FI / / VX-2-FI / / / / / / VX-FI / VX-3-FI / / / Higher capacities available on demand. *Energy meter not included. 24

25 FLATSTATION PRODUCT GUIDE Danfoss FlatStations - 4 Series Cooling Indirect FlatStation for cooling Circuit diagram - example V F DC supply CO supply DC return A bar CO return A Heat exchanger CO F Electronic controller 4 Safety valve 9 Strainer 10 Circulator pump 14 Sensor pocket, energy meter 16 Outdoor sensor 19 Surface sensor 20 Filling/drain valve 24 Delivered loose with unit 26 Pressure gauge 27 Actuator way motorized valve 31 controller 38 Expansion tank 41 Fitting piece, energy meter 48 Air vent, manual Technical parameters: Nominal pressure: PN 16 DC supply temperature: T max = 50 C T min = 0 C Brazing material (HEX): Copper Weight incl. cover: Cover: Dimensions (mm): Without cover: H 605 x W 580 x D 270 With cover: H 675 x W: 625 x D 295 Approx. 50 kg (incl. packing) Fully insulated galvanized steel Connections: 1 District cooling (DC) supply 2 District cooling (DC) return 3 Cooling (CO) supply 4 Cooling (CO) return 5 Safety relief discharge connection Connections sizes: DC + CO: G ¾ (int. thread) Options: Outdoor temperature sensor Cooling: Capacity examples FlatStation type VX-C Cooling capacity [kw] Supply flow Primary Return flow Primary Flowrate Primary [l/m] Pressure loss Primary* [kpa] Supply flow Secondary Return flow Secondary Flowrate Secondary [l/m] VX-C VX-C VX-C Higher capacities available on demand *Energy meter not included 25

26 FLATSTATION PRODUCT GUIDE Danfoss FlatStations - 5 Series BS Self-acting direct FlatStation Circuit diagram - example DHW DCW DH supply 62B B Water heater 1 Ball valve 7 Thermostatic valve 9 Strainer 14 Sensor pocket, energy meter 31 Differential pressure controller 41 Fitting piece, energy meter 62B Pressure absorber w/non-return valve 69 On / off valve HE supply DH return HE return Technical parameters: Nominal pressure: PN 10 DH supply temperature: T max = 120 C DCW static pressure: p min = 0,5 bar Brazing material (HEX): Copper Weight incl. cover: Cover: 20 kg (incl. packing) Whitelacquered steel sheet Dimensions (mm): Without cover: H 760 x W 525 x D 110 mm With cover (mount on wall variant): H 800 x W 540 x D 242 mm Connections: 1 District heating (DH) supply 2 District heating (DH) return 3 Domestic hot water (DHW) 4 Domestic cold water (DCW) 5 Heating (HE) supply 6 Heating (HE) return Connections sizes: DH + HE: G ¾ (int. thread) DCW + DHW: G ¾ (int. thread) Options: Mounting rail with ball valves Safety valve (8 bar) Room thermostat Connection for hot water circulation Hot water circulation pump Thermometer DHW: Capacity examples FlatStation type VMTD-F-B DHW capacity [l/min] DHW capacity [kw] Supply flow Primary Return flow Primary CW/DHW Flow rate Primary [l/m] Pressure loss Primary* [kpa] / VMTD-F-B / / / VMTD-F-B / / / VMTD-F-B / / / VMTD-F-B / / Higher capacities available on demand. *Energy meter not included. 26

27 FLATSTATION PRODUCT GUIDE Danfoss FlatStations - 5 Series DS Fully Insulated Self-acting direct FlatStation Circuit diagram - example Mounting rail Option DH supply DHW DHW recirc. DCW 62B B Heat exchanger M Electrical wiring box 2C Single check valve incl. circulation pipe 9 Strainer 14 Sensor pocket, energy meter 21 To be ordered separately Fitting piece, energy meter ¾ x 110 mm 62B Pressure absorber w/non-return valve 63 Sieve TPV HE supply DH return HE return Technical parameters: Nominal pressure: PN10 DH supply temperature: T max = 120 C DCW static pressure: p min = 1 bar Brazing material (HEX): Copper Max pri. pressure P max = 4.5 bar DHW setting range: T = C Weight incl. cover: 20 kg (incl. packing) Connections: 1 District heating (DH) supply 2 District heating (DH) return 3 Domestic hot water (DHW) 4 Domestic cold water (DCW) 5 Heating (HE) supply 6 Heating (HE) return Connections sizes: DH + HE: DCW + DHW: Options: Safety valve (8 bar) Room thermostat Thermometer G ¾ (int. thread) G ¾ (int. thread) Insulation cover: Anthracite grey EPP Dimensions (mm): With insulation (mounted on wall variant) H 555 W 528 D DHW: Capacity examples Heating: Capacity examples DHW: Capacity examples Supply Return Pressure Heating: Capacity examples DHW DHW Heating Heating Pressure FlatStation flow flow DHW loss Capacity Supply Return Flow Tap load Pressure FlatStation Flow rate FlatStation type DHW DHW Primary primary CW/ FlatStation CapacityHeating Circuit t Heating loss* Pressure loss Flow rate Primary [kw] flow flow rate [l/m] loss type [l/m] type capacity capacity DHW type [kw] capacity circuit [kpa] Primary* Primary Primary Primary [kpa*] Primary Primary* VMTD-I-FI [l/min] 32,3 [kw] /45 VMTD-I-FI [kw] Δt [kpa] [l/m] 22 [l/m] 13.3 [kpa] , / VMTD-I-x-FI VMTD-I-FI-1/ VMTD-I-1-FI / , / VMTD-I-FI-1/ / VMTD-I-FI / * Energy meter VMTD-I-FI-1/2 not included , / / Higher capacities available on demand / / , / / VMTD-I-2-FI VMTD-I-FI / / , / / Higher capacities available 59 on demand / *Energy meter not included. 27

28 FLATSTATION PRODUCT GUIDE Danfoss FlatStations - 7 Series BS Self-acting indirect FlatStation Circuit diagram - example DHW DCW 62B A Plate heat exchanger HE B Water heater 1 Ball valve 2B Double check valve, WRAS 4 Safety valve 6 Thermostatic/non-return valve 7 Thermostatic valve 9 Strainer 10 Circulation pump Electrical wiring box 14 Sensor pocket, heat meter 18 Thermometer 20 Filling/drain valve 24 Delivered loose with unit 26 Manometer Expansion vessel 41 Fitting piece, heat meter 48 Air escape, manual 62B Pressure absorber w/non-return valve 69 DH supply HE supply DH return 24 HE return Technical parameters: Nominal pressure: PN 10* DH supply temperature: T max = 120 C DCW static pressure: p min = 0,5 bar Brazing material (HEX): Copper * PN 16 versions are available on enquiry Weight incl. cover: Cover: Dimensions (mm): Without cover: H 810 x W 525 x D 360 With cover: H 800 x W 540 x D kg (incl. packing) Whitelacquered steel Connections: 1 District heating (DH) supply 2 District heating (DH) return 3 Domestic hot water (DHW) 4 Domestic cold water (DCW) 5 Heating (HE) supply 6 Heating (HE) return Connections sizes: G ¾ (int. thread) Options: Cover, white-lacquered steel (Design Jacob Jensen) Safety valve Pipe insulation heating Safety thermostat surface type Weather compensation, electronic controls circuit Room thermostat DHW: Capacity examples, 10 C/50 C Heating: Capacity examples DHW: Capacity examples Heating: Capacity examples Available DHW Supply Return DHW/ Pressure Flow DHW Pressure Heating Supply Heating Pressure Pressure Flow Flow FlatStation DHW DHW CW/ Supply Return Min. diff. FlatStation Capacity DCW loss Tap FlatStation pump Residual flow flow rate loss FlatStation Capacity Heating flow Pri. circuit loss Heating loss Flow rate rate rate Flow rate type capacity capacity DHW flow flow pressure pressure pump head type [kw] Primary Pri. Primary Pri. Primary Pri.* Primary* load type type[kw] capacity Pri.* circuit Sec. Primary Pri. Sec. Secondary VVX-B [l/min] [kw] Primary Primary Primary* Sec. Secondary [l/m] [kpa] [l/m] [kpa] VVX-B [kw] (l/m) [kpa] [kpa] [l/m] [l/m] [l/m] [kpa] [kpa] [kpa] / VVX-B-1-x VVX-B-1-x /50 10/ / / / VVX-B-x / / VVX-B-x / VVX-B-2-x / / VVX-B-2-x / / / /50 10/ VVX-B-x / / VVX-B-3-x / /45 10/ VVX-B-x / / VVX-B-3-x VVX-B-4-x / / / / VVX-B-x / / * Heat 27 meter not 66.2 included / / / VVX-B-4-x / VVX-B-x / / / Higher capacities available on demand Higher capacities available on demand *Energy meter not included 28