Daikin Altherma Flex type. Application Guide

Transcription

1 Daikin Altherma Flex type Application Guide Version 1.00 Page1

2 Table of Contents 0 INTRODUCTION HYDRAULICS Hydraulic components of the indoor units Hydraulic layout of the system No use of secondary pump(s) Use of a secondary pump Minimum watervolume in the system Sizing of the collectors and decoupling bottle Sizing of the collector Function of the de-coupling bottle Sizing of the de-coupling bottle Example of collector and de-coupling bottle sizing Secondary flow versus primary flow Dirt seperator WIRING One remote control per indoor unit Group control THERMOSTAT CONTROL Heating only units Reversible units (Heating and cooling) DOMESTIC HOT WATER HEATING Basic sizing of the required re-heat capacity and storage volume Calculation of the required re-heat capacity: Calculation of the required storage volume considering no re-heat during tapping Calculation of the required storage volume considering reheat during tapping Boundary conditions Using the excell calculation sheet to calculate storage volume and reheat capacity Requirements for 3th party tank Some examples of sizing DHW heating in combination with room heating & cooling Dedicated DHW heating with 3th party tank BI-VALENT APPLICATION Reasons to use a bi-valent system Hydraulic layout Boiler located in secondary circuit Boiler located in the primary circuit Page2

3 0 INTRODUCTION This application guide gives guidelines for both system sizing and system design, of applications with several HT-Altherma units put in parallel used for central heating,cooling and/or hot water heating. The guideline applies to the outdoor models EMRQ8/10/12/14/16AAY1 combined with indoor units EKHVMRD50/80AAV1, EKHVMYD50/80AAV1, EKHBRD011/014/016ACV1 and EKHBRD011/014/016ACY1. The guideline does not cover specific installation or operation instructions. For this information, please refer to the corresponding installation and operation manuals. It is the intention that the guideline will be updated and extended by experience gathered on installations all over Europe. For this reasons, please mail all your suggestions, remarks or questions to Page3

4 1 HYDRAULICS 1.1 Hydraulic components of the indoor units. Hydraulic components ( and refrigerant components) inside the indoor unit can be found in schematic below. Refer also to the installation manual. Heating only units: (EKHBRD* / EKHVMR*) Page4

5 Heating and cooling units: (EKHVMY*) Page5

6 1.2 Hydraulic layout of the system No use of secondary pump(s) When the static height of the heat emission system is low, the units can be connected in parallel and connected directly to the heat emission system. Every unit must be foreseen of a none return valve. None return valves Pressure differential vale For pumps operating in parallel the pump curve of the pumps operating together can be drawn by summing the flow at same ESP. It means, the ESP of the pumps operating together is not increased compared to 1 pump operating! For this reason, make sure that the pumps can overcome the static height! See below example. The example shows 1 pump connected to the heating system results in a flow of 35 l/min, ESP=60kPa 3 pumps in parallel connected to the same system will only result in a flow of about 42l/min (at ESP=90Pa) and not 35x3 = 105 l/min! Resistance curve heating system 3 pumps in parallel 1 pump As to make sure all units get same flow, use collectors for connection or put them in Tichelman. ATTENTION POINTS: Make sure to mount a none return valve on every unit Make sure that static height of pumps is enough Make sure to connect the units to a collector or put them in Tichelman. Page6

7 1.2.2 Use of a secondary pump In most cases, the resistance of the system will be too high. A secondary pump(s) has to be used together with a decoupling bottle, because the flow through the units must not be influenced by the secondary pump(s). Primary circuit Secondary circuit None return valves collectors or Tichelman layout De-coupling bottle None return valves ATTENTION POINTS: Make sure to mount a none return valve on every unit Make sure to use a decoupling bottle Make sure to connect the units to a collector or put them in Tichelman. Page7

8 1.3 Minimum watervolume in the system. As to guarantee good system operation, it is required to have 15l water volume per installed indoor unit. Only the watervolume that can not be shut off by valves or stopped pumps, is taken into account! Example 1: Units in below configuration work independent from the secondary pump. If secondary pump is stopped, and units still operate, water will only flow through the decoupling bottle. Example 2: Units in below configuration are put ON with external contact only when secondary pump is in operation. First radiator group always get flow since no thermostatic valves installed. Considered volume Considered volume When using the de-coupling bottle as a storage vessel, please take into account the construction guidelines of the de-coupling bottle as explained in Page8

9 1.4 Sizing of the collectors and decoupling bottle Sizing of the collector When the units are connected to a common collector, it must be made sure that all units get the same water-flow, independent from their position on the collector. For this reason, the watercollector is sized such, that the speed in the collector is below 0.9m/s. Calculate the required collector diameter from the volume flow. The volume flow has to be calculated from the design capacity.: Step 1 : Calculation of the volume flow: Q V = ρ.c w. T V [m³/s] = Volume flow of the system at design capacity (1) Q [kw] = Design capacity ρ [kg/m³] = Density of water = 1000kg/m³ Cw [kj/kg.k] = Specific heat capacity of water = 4,186 kj/kg.k T = T of the system at design condions (2) (1) As to guarantee the transfer of the heat from the primary circuit to the secondary circuit, the primary circuit flow should be a little higher than the secondary flow. (2) The units have variable speed pumps, adapting their speed as to achieve T as set on the unit control. (see installation manual: Start up and configuration) Step 2: Calculation of minimum required internal diameter: 4.V Di = v.π Di [m] V [m³/s] v [m/s] = Minimum required internal diameter of collector = Volume flow of the system at design capacity = water speed (0,9m/s) Page9

10 1.4.2 Function of the de-coupling bottle The decoupling bottle guarantees independent operation of the pumps of the primary side and secondary side. In the de-coupling bottle, the water-speed is low which makes it a very suitable place to purge air and deposit dirt. Air Purge PRIMARY SIDE SECONDARY SIDE Valve to remove collected dirt The flow in the de-coupling bottle will change depending on the flow/load of the primary/secondary circuit as shown below. Primary flow=secondary flow No load (No secondary flow) Primary flow >secondary flow Primary flow < secondary flow) In this case the temperature to the secondary will be lower than the temperature coming from the primary. For reasons of energy saving, this should be avoided. For this reason it is advised to use a variable speed pump on the secondary side. Page10

11 1.4.3 Sizing of the de-coupling bottle The de-coupling bottle must have a very low hydraulic resistance. For this reason, the diameter D of the de-coupling bottle is sized such, that the speed in the bottle is below 0.1m/s. Moreover, the bottle is preferably constructed as shown below. D From heatpumps D D To secondary circuit To heatpumps >D > D D From secondary circuit D to be calculated as explained in Sizing of the collector. (waterspeed v=0.1m/s) The bottle is mounted vertically, with the hot side to the top. As to avoid short circuit of the primary and secondary circuit, it should be taken care that D is also not sized too big. If the decoupling bottle is sized bigger, as to serve also as a buffer vessel, inlet and outlet pipes must be constructed as shown in below figures, as to avoid short circuits from primary and secondary side. Pipes run in the vessel and are cut diagonally as shown. Pipes run through the buffer with appropriate holes. Page11

12 1.4.4 Example of collector and de-coupling bottle sizing.. 8x(EMRQ16+3xEKHBRD016) units installed. Requirements secondary circuit: - Capacity : 280 kw - Supply/return water : 70 C/55 C Calculation of secondary flow ==> Flow = 280/(4,186.(70-55)) = 4,46 l/s = 267 l/min Calculation of primary flow ==> Primary flow >= 267 l/min ( T setting pump =< 15 C) Volume flow 4,46 l/s Water speed =< 0,1m/s 4x(4,46/1000) Di >= >= 0,24m >= 24cm 0,1x3,14 Volume flow 4,46 l/s Water speed =< 0,9m/s 4x(4,46/1000) Di >= >= 0,08m >= 8cm 0,9x3,14 Volume flow 1,11 l/s Water speed =< 0,9m/s 4x(1,11/1000) Di >= >= 0,04m >= 4cm 0,9x3,14 Integrated circulators, working on fixed DT=<15 C Page12

13 1.4.5 Secondary flow versus primary flow It is very important that the primary flow (flow of the heat-pumps) is bigger than the secondary flow to the system. This will avoid back-mixing of the return water, and thus sending water at lower temperature to the heating system than the leaving water of the heat-pumps. See below example: Assume the secondary flow at design condition is 61l/min, design temperature supply 50 C/ return 43 C. The radiators are designed to dissipate 30kW heating at those conditions. CASE 1: Units are configured to operate with T=5 C. (=86l/min at 30kW), and setpoint = 50 C This will result in following flows and temperatures in the system. 86 l/min 50 C 61 l/min 50 C 25 l/min 30 kw 86 l/min 45 C 61 l/min 43 C CASE 2: Units are configured to operate with T=10 C. (=lower flow), and setpoint = 50 C This will result in following operation. The heat-pumps will reduce their flow until they reach DT=10 C. (as their setpoint = 50 C, this means 50-10=40 C). The system will find a balance as shown below. 35 l/min 50 C 61 l/min 45,6 C 26 l/min 24 kw Since the flow of the heatpumps is lower than the secondary flow, return water of the secondary loop is returned through the decoupling bottle to the supply of the secondary loop. This reduces the supply temperature, and thus the heating capacity dissipated by the radiators! ATTENTION POINTS: 35 l/min 40 C 61 l/min 40 C Make sure to design the flow of the primary heat-pump loop bigger than the design flow of the secondary loop. (The lower the T setting of the heat-pumps, the bigger the flow will be. Refer to installation manual) 1.5 Dirt seperator Page13

14 In old installations, it is highly recommended to: - Flush the system before putting the heatpumps into place. - install a dirt separator with magnet, as to avoid blockage of the mesh filters, pumps and or heatexchangers in the heatpumps. The dirt separator separates off these impurities, which are mainly made up of particles of sand and rust, collecting them in a large collection chamber, from which they can be removed even while the system is in operation. The magnet boosts the separation of magnetic dirt (magnetite). The separator is to put on the common return pipe of the (old) secondary system. ATTENTION POINTS: Make sure to flush old systems Make sure to put a magnetic filter in old systems with iron piping. Page14

15 2 WIRING For the electrical wiring work and system overview of field wiring please refer to the appropriate installation manuals. The schematics below only explain communication wiring. 2.1 One remote control per indoor unit F1/F2 communication wiring between outdoor & indoors. P1/P2 wiring between indoor and its remote controller. (every unit is standard delivered with 1 remote controller) 2.2 Group control The remote controller can be connected to control 1 group of indoor units. This implements that all indoor units have same configuration and same settings. Thus; it is e.g. not possible to connect 1 indoor unit without tank and 1 indoor with tank to the same controller. For the same reason, it is also not allowed to connect heating only units with reversible units to the same remote control! 1 remote controller can be connected to indoor units connected to other outdoors, as long as the settings are the same. 1 remote controller can be connected to maximum 16 indoor units. Page15

16 Note: Group control has the advantage that settings for several indoor units with same configuration, have to be entered at only 1 remote controller. However, the dis-advantage is that the remote controller will only show the values (leaving water temperature, entering water temperature, DHW temperature if DHW sensor is installed - ) of unit 0. (the connected indoors get automatically an address of 0 to 15) The only way to determine the units addresses is running their pumps by entering the field settings as described below. Field setting Value 10 = Unit 0 Value 11 = unit 1 Value 25 = unit 15 All units will be put thermostat OFF and the pump of the corresponding unit will run at 4000 rpm (during 10 minutes, after that the field setting is reset). The appropriate unit can be identified by listening to the pump noise. If one or more units have A6 error (malfunction of pump), should be set to the value of 2 and this will operate the pumps of all the indoor units not having the A6 error. Page16

17 3 THERMOSTAT CONTROL 3.1 Heating only units The thermostat control of the hydro-box is determined by setting following parameters :Optional thermostat installed. Defines whether an external thermostat (external voltage free contact) is installed. 6-01=0 No optional thermostat installed. (Default value) 6-01=1 Optional thermostat installed Demand PCB EKRP1AHTA (optional) must be installed to connect the external thermostat : Remote temperature control: Defines whether the remote controller is used as room thermostat. 8-00=0 Remote controller is NOT used as room thermostat. 8-00=1 Remote controller is used as room thermostat (Default value) (Note: 8-00 automatically jumps to 0 when 6-01 is put to 1) The table on the next page gives an overview, depending on the setting of above parameters, on - Compressor ON/OFF - Circulation pump ON/OFF Page17

18 6-01 = 0 AND 8-00 = 0 (No external thermostat installed and remote controller not used as room thermostat) 6-01 = 1 AND 8-00 = 0 ( external thermostat installed and remote controller not used as room thermostat) 6-01 = 0 AND 8-00 = 1 (Default setting) (No external thermostat installed and remote controller used as room thermostat) LWT = Leaving water temperature / RWT = Return water temperature / RT = Room temperature SP = Setpoint for leaving water temperature or room temperature Page18

19 3.2 Reversible units (Heating and cooling) The thermostat control of the hydro-box is determined by setting following parameters :Optional thermostat installed. Defines whether an external thermostat (external voltage free contact) is installed. 6-01=0 No optional thermostat installed. (Default value) 6-01=1 Optional thermostat installed (one contact for cooling/one contact for heating) 6-01=2 Optional thermostat installed(one contact for ON-OFF/ one contact for cool/heat changeover) Demand PCB EKRP1AHTA (optional) must be installed to connect the external thermostat : Remote temperature control: Defines whether the remote controller is used as room thermostat. 8-00=0 Remote controller is NOT used as room thermostat. 8-00=1 Remote controller is used as room thermostat (Default value) (Note: 8-00 automatically jumps to 0 when 6-01 is put to 1or2) The table on the next page gives an overview, depending on the setting of above parameters, on - Compressor ON/OFF - Circulation pump ON/OFF Page19

20 6-01 = 0 AND 8-00 = 0 (No external thermostat installed and remote controller not used as room thermostat) 6-01 = 1 AND 8-00 = 0 ( external thermostat installed and remote controller not used as room thermostat) Page20

21 8-00 = 0 AND 6-01 = = 1 AND 6-01 = 0 (default setting) LWT = Leaving water temperature / RWT = Return water temperature / RT = Room temperature SP = Setpoint for leaving water temperature or room temperature Page21

22 4 DOMESTIC HOT WATER HEATING 4.1 Basic sizing of the required re-heat capacity and storage volume The 2 most important parameters for basic sizing are: The peak tap. Determined by the maximum volume of DHW that will be tapped at a certain temperature in a certain period. The required re-heat time (time between 2 tappings) A system will always be a balance between a certain storage volume to overcome the peak tap, and a certain capacity to re-heat the tapped volume. The bigger the storage volume, the smaller the re-heat capacity can be and vice versa Calculation of the required re-heat capacity: The required re-heat capacity can easily be calculated as follows: Re-heat capacity = Tapped_energy / reheat_time Re-heat capacity = Vtap.Cw.(Ttap-Tcold)/reheat_time Re-heat capacity = Required reheat capacity [kw] Vtap = Tapped volume [l] Cw = Specific heat capacity water [kj/kg.k] Ttap = Tapping temperature [ C] Tcold = Inlet temperature cold water [ C] Re-heat time = Time between start of reheating and next tap [s] Ex: 5200l of DHW will be tapped at 43 C in 1 hour. The required re-heat time is 8 hours. The entering water temperature is assumed to be 10 C Required re-heat capacity= 5200l.4,186 kj/kg.k.(43-10) C/(8*3600s) = 25 kw Note 1: The above doesn t take into account heat losses of the tank. Heat losses of the tank should be added to the required re-heat capacity. When a recirculating loop is used, heat losses can be big. Note 2: The re-heat time is the time between the start of the re-heat and the start of the next tapping. The start of the re-heat will depend on the setting of the re-heat minimum temperature (see installation manual). A high setting will result in a quick start of re-heating during the tapping, a low setting will result in a start of the re-heating at a later stage of the tapping. To calculate on the safe side, re-heat time can be considered as being the time between the end of the tapping and the start of the next tapping. This may however lead to oversizing, especially when the tapping period is long compared to the time between 2 tappings. Page22

23 4.1.2 Calculation of the required storage volume considering no re-heat during tapping The tapped energy in above example has to be delivered in 1 hour time. If no storage would be foreseen, it would mean that a re-heat power of 5200l.4.186kJ/kg.K.(43-10) C/3600s = 200 kw must be foreseen to overcome the peak tap (instant heater). As an alternative, energy can be stored to overcome the peak tap. To overcome the peak tap: The stored energy >= tapped energy The stored energy can be calculated as follows: Stored_energy = Vtank.Cw.(Ttank,start-Tcold) [kj] Vtank = tank volume [l] Cw = Specific heat capacity water [kj/kg.k] Ttank,start = Tank temperature at start tapping [ C] Tcold = Temperature cold water [ C] The above assumes that the complete tank volume can be tapped at tank temperature. It means that from e.g. a 500l tank at 60 C, 500l water at 60 C can be tapped. This is of course not true, since the cold water entering the tank will mix with the hot water, and in reality, e.g. only 450l can be tapped at 60 C. This is quantified by the efficiency of the tank.(η). Tank efficiency = hot water that can be tapped at tank temperature from a tank/ tank volume. In the above example, the tank efficiency = 450/500 = 90% Stored_energy =η Vtank.Cw.(Ttank,start-Tcold) The tapped energy can be calculated as follows: Tapped energy = Vtap.Cw.(Ttap-Tcold) [kj] Vtap = Tapped volume [l] Cw = Specific heat capacity water [kj/kg.k] Ttap = Tapping temperature [ C] Tcold = Temperature cold water [ C] From the above: η Vtank. Cw.(Ttank,start-Tcold) >= Vtap.Cw.(Ttap-Tcold) Vtap.(Ttap-Tcold) Vtank >= η. (Ttank,start-Tcold) In the above example it means, if the set-point of the tank temp. = 60 C and tank efficiency=0.96, the volume of the tank must be: Vtank >=5200/0.96*(43-10)/(60-10) = 3575l Note: Typical values for tanks efficiencies are 0.8 to However, for storage tanks of the run through type (as ROTEX) the efficiency is a lot lower, since the tank temperature must be higher than the tapping temperature as to be able to transfer heat through the heatexchanger. The efficiency of this type of tanks ranges from 0.4 to 0.6. The efficiency reduces with the increase on the tapping flow. Page23

24 4.1.3 Calculation of the required storage volume considering reheat during tapping The previous assumes that no re-heating takes place during the tapping. In reality, re-heating already takes place during tapping. Depending on the setpoint of re-heat minimum temperature refer to installation manual the re-heating will start at a certain point during the tapping. Calculating the tank considering that no reheat takes place during the tapping is on the safe side, but will lead to over-dimensioning of the tank.(especially with long tapping periods and if big re-heat capacity is available). If the re-heat minimum temperature is set very close to the reheat maximum temperature of the tank, it can be assumed that re-heating will start quite fast after tapping and will thus last a big part of the entire taptime. Stored energy >= tapped energy reheat energy η.vtank.cw.(ttank-tcold) >= Vtap.Cw.(Ttap-Tcold) re-heat capacity. time Vtap.Cw.(Ttap-Tcold) reheat_power. time Vtank >= η Cw.(Ttank-Tcold) At the limit, it can be considered that the re-heat starts immediately after tapping time in above formula = tapping time In the above example it means: If the considered re-heat capacity = 25kW (minimum required to reheat tank by next tapping, refer to Calculation of the required re-heat capacity) Vtank >=(5200*4.186*(43-10)-25*3600)/(0,96.4,186.(60-10))>=3127 l This assumes that re-heating starts immediately after the tapping Boundary conditions 3127l < Vtank < 3575 l, depending on the setting of the minimum reheat temperature. Beside the required re-heat capacity and the required storage volume, 2 boundary conditions are to be met. 1. The tapflow per tank shall not exceed the maximum allowed tap-flow of the tank. Too big tap-flow of the tank will destroy the stratification of the tank and thus reduce the efficiency, and can also lead to excessive pressure losses. The tankflow can easily be calculated as: (Ttap Tcold) Tank Flow = Tap Flow (Ttank Tcold) In the example, tank flow = (43 C-10 C)/(60 C-10 C).5200l/60min = 57.2l/min 2. The tank must be able to dissipate the reheat capacity received from the heatpump. For this reason, it is very important for 3th party tanks that the capacity of the heating coil in the tank is sufficient. Refer to 4.3 Requirements for 3th party tank. Page24

25 4.2 Using the excell calculation sheet to calculate storage volume and reheat capacity Solution with Daikin tank The excel calculation sheet allows you to enter the parameters as described above (see yellow cells) and shows solutions with both EKHTS260 and EKHWP500 tanks. The solution columns show: Qrh : Re-heat capacity. This is heat-pump capacity used to re-heat the tank. The solution with the smallest possible re-heat capacity is shown first. Vtank : Required storage volume Qtity : Nr of EKHTS260 / EKHWP500 tanks required to cover the volume. Power/tank : Re-heat capacity per tank. This is limited to 16kW/tank for EKHTS260 and 14kW/tank for EKHWP500 Flow/tank :Allowed flow per tank. This is limited to 12l/min/tank for EKHTS260 and 16l/min/tank for EKHWP500 Re-heat time : Time after which the tank is reheated after tapping has stopped. When entering the example of 5200l, the sheet shows a required tank volume of 3266l with a capacity of 25kW. This is in between the values calculated, since the sheet takes into account the start of the reheating by means of the entered minimum reheat temperature. Entering a value of 60 C will give 3127l, since then it is assumed reheat starts immediately after start tapping. The sheet also shows that the storage volume is reduced if bigger reheat capacity is chosen. If the reheat capacity is e.g. increased to 90 kw, the storage volume can be reduced to 2318l, taking into account a minimum reheat temperature of 43 C. Page25

26 Solution with 3th party tank The example above results because of the big tappingvolume in a big tank volume. It might not be feasible to realize the project with Daikin tanks. For this reason, the sheet allows also to enter the volume of 3th party tank, the number of tanks used and the efficiency of the tanks. It shows the minimum required reheat capacity to be used with the tanks, the reheat capacity per tank and from this the required tank heat exchanger capacity, - refer also to 4.3 Requirements for 3th party tank.- the flow per tank and the reheat time. If for the example above, 2x1500l tanks would be used, with an efficiency of 0.96, the required re-heat capacity is 45 kw REQUIRED RE-HEAT POWER FOR A GIVEN TANK Tank Volume of 3th party tank 1500 l Qrh Vtank Qtity Power/tank Flow/tank Re-heat time Nr. of tanks 2 44, l 2 22 kw 28,6 l/min 4,4 hrs Efficiency 0,96 Adviced HEX capacity >2,25 kw/ C Etap ,6 199, >2,19 m²/tank Etank ,44 Ereheat = 32, Possible tap at 43 C without reheat 4364 l This is: heatexchanger capacity = (inlet temp. HEX+outlet temp. Hex)/2-Tank_temperature Example: Manufacturer specifies: 30kW at inlet/outlet = 80 C/60 C and tank temperature = 20 C. => It means heat exchanger capacity = 30/(70-20)=0,6kW/ C 4.3 Requirements for 3th party tank. It is adviced to use a Daikin supplied DHW tank (EKHTS*, EKHWP*), since these tanks are optimized for operation in conjunction with the Daikin heat-pump. In case a 3th party tank is used, the capacity of the heating coil is of the utmost importance. The heat exchanger capacity of the tank per C [kw/ C] > = connected capacity to the tank [kw]/10 The heat exchanger capacity of the tank per C can be calculated from manufacturers data as follows:: heatexchanger capacity heat exchanger capacity of the tank per C = (inlet temp. HEX+outlet temp. Hex)/2-Tank_temperature Example: Manufacturer specifies: 30kW at inlet/outlet = 80 C/60 Cand tank temperature = 20 C. Heat exchanger capacity of the tank per C = 30/((80+60)/2-20) = 0.6 kw/ C It means only 6kW heat output per tank should be connected! If the capacity of the coil is not known, as a rule of thumb the coil surface can be used. The coil surface of the heat exchanger should be at least 0.098m²/kW connected capacity. e.g.: Tank heated with 30kW heatpump output connected to it, should have a coil with a heating capacity of 30/10 = 3kW/ C (it means 3*((80+60)/2-20) = 150 kw at conditions Tin/Tout = 80 C/60 C and tank temperature = 20 C. If capacity is not known, it should be checked that the surface of the tank coil =30*0.098 = 2.94m². Page26

27 4.4 Some examples of sizing - Example 1: Big peak tap with short re-heat time. A Jacuzzi bath needs to be filled in 10 minutes. 500l water at 43 C. Required re-heat time of the tank: 1 hour. Assumed cold water temperature=10 C, tank temperature setpoint = 60 C, tank efficiency=0.96 (EKHTS260) Solution with Daikin tanks: Required re-heat capacity: = 500l.4,186 kj/kg.k.(43-10) C/3600s = 19,2 kw Vtank (no reheat during tap) = 500l.(43-10) C/(0.96.(60 C-10 C)) = 343,7 l (500l.4,186kJ/kg.K.(43-10) C-19.2kW.600s) Vtank (reheat after start tap) = (0.96.4,186.(60-10)) C = 286 l 286l<Vtank<344l Bounderies: 19,2 kw if 2xEKHTS260 = 9.6 kw/tank < 16kW/tank = O.K. Bounderies: Tank flow = (43-10) C/(60-10) C.500l/600s = 0.55l/s = 33l/min. If using 2 tanks = 16.5l/min/tank > 12l/min/tank 3 tanks required. The Excell sheet gives as output: 20 kw minimum re-heat capacity, (15kW too small, jumps to 5kW higher solution) with 289l storage tank EKHTS260, but because of the boundaries,3 tanks are mentioned as solution. Bigger re-heat capacities will lead to shorter reheat times, but not to fewer tanks because of the boundaries. Solution with 3th party tank: Tank Volume of 3th party tank 500 l Qrh Vtank Qtity Power/tank Flow/tank Re-heat time Nr. of tanks 1 17 kw 500 l 1 17 kw 33,0 l/min 1,0 hrs Efficiency 0,9 Adviced HEX capacity kj kwh >1,68 kw/ C 19, >1,64 m²/tank Etap Etank ,1625 Ereheat = -6, REQUIRED RE-HEAT POWER FOR A GIVEN TANK Possible tap at 43 C without reheat 682 l This is: heatexchanger capacity = (inlet temp. HEX+outlet temp. Hex)/2-Tank_temperature Example: Manufacturer specifies: 30kW at inlet/outlet = 80 C/60 C and tank temperature = 20 C. => It means heat exchanger capacity = 30/(70-20)=0,6kW/ C This document is for information only and does not constitute an offer binding upon Daikin. Daikin has compiled the content of this document to the best of its knowledge. No express or implied warranty is given for the completeness, accuracy, reliability or fitness for particular purpose of its content. Specifications are subject to change without prior notice. Daikin explicitly rejects any liability for any direct or indirect damage, in the broadest sense, arising from or related to the use and/or interpretation of this document. The program takes into account that re-heat starts already during the tapping (high minimum reheat temperature). This results in slightly lower required reheat capacity. 17 kw will reheat the tank by the next tapping. Required coil size of the tank > 1.64m² Page27

28 - Example 2: Big tap volume with longer reheat time. A hotel with 50 beds expects a maximum tap of 50x50=2500l at 43 C between 6:00 and 8:00 and another tap between 18:00 and 20:00. Tap time = 2 hours, reheat time = 10 hours (8:00 to 18:00) Assumed tank temperature setting is 60 C, cold water temperature 10 C. Solution: - Re-heat capacity = 2500l.4,186kJ/kg.K.(43-10) C/(10hrs.3600s)=9.6 kw - Vtank (no reheat during tapping) = 2500l.(43-10) C/(0,96.(60-10) C) =1718l 2500l.4,186.(43-10) C-9.6kW.2h.3600s - Vtank (reheat during tapping) = (0,96.4,186kJ/kg C.(60-10) C) = 1375l Reheat capacity = 9.6 kw, 1375l<tank volume <1718l The Excell sheet gives as output: Minimum reheat capacity 10 kw, with 6xEKHTS260 tanks or 6 EKHWP500 (program takes into account reheat starts already during tapping). Tank volume could be decreased by increasing the reheat capacity. e.g. increasing reheat to 25 kw, with 4xEKHTS260 or 4xEKHWP500 DHW REQUIREMENT BASED ON REQUIRED PEAK TAPPING VOLUME USER DATA REQUIRED NR. OF DAIKIN TANKS IN FUNCTION OF RE-HEAT POWER Tap volume Vtap 2500 l Tap time Tap_time 7200 s EKHTS260 EKHWP500A Tap temperature Tap_temp 43 C Bounderies Bounderies Qrh Vtank Qtity Power/tank Flow/tank Re-heat time Qrh Vtank Qtity Power/tank Flow/tank Re-heat time Cold water temp cold_temp 10 C 5 kw 1572 l 7 0,7 kw 2,0 l/min 17,6 hrs 5 kw 3148 l 7 0,7 kw 2,0 l/min 17,2 hrs Tank temperature 60 C 10 kw 1420 l 6 1,7 kw 2,3 l/min 7,9 hrs 10 kw 2853 l 6 1,7 kw 2,3 l/min 7,6 hrs Minimum reheat temperature 50 C 15 kw 1260 l 5 3,0 kw 2,8 l/min 4,7 hrs 15 kw 2544 l 6 2,5 kw 2,3 l/min 4,4 hrs 20 kw 1093 l 5 4,0 kw 2,8 l/min 3,1 hrs 20 kw 2221 l 5 4,0 kw 2,8 l/min 2,8 hrs Required reheat time (end tap to start next) 10 hrs 25 kw 919 l 4 6,3 kw 3,4 l/min 2,1 hrs 25 kw 1882 l 4 6,3 kw 3,4 l/min 1,8 hrs 30 kw 736 l 3 10,0 kw 4,6 l/min 1,4 hrs 30 kw 1528 l 4 7,5 kw 3,4 l/min 1,2 hrs Efficiency max. reheat max tap 35 kw 544 l 3 11,7 kw 4,6 l/min 0,9 hrs 35 kw 1157 l 3 11,7 kw 4,6 l/min 0,7 hrs [kw/tank] [l/min.tank] 40 kw 343 l 3 13,3 kw 4,6 l/min 0,5 hrs 40 kw 767 l 3 13,3 kw 4,6 l/min 0,4 hrs EKHTS260 0, kw 131 l 3 15,0 kw 4,6 l/min 0,2 hrs 45 kw 356 l 3 15,0 kw 4,6 l/min 0,1 hrs EKHWP500 f(flow &Tank_temp-Tap_temp) kw 0 l 3 16,0 kw 4,6 l/min 0,0 hrs 48 kw 103 l 3 16,0 kw 4,6 l/min 0,0 hrs 48 kw 0 l 3 16,0 kw 4,6 l/min 0,0 hrs 48 kw 103 l 3 16,0 kw 4,6 l/min 0,0 hrs 48 kw 0 l 3 16,0 kw 4,6 l/min 0,0 hrs 48 kw 103 l 3 16,0 kw 4,6 l/min 0,0 hrs 48 kw 0 l 3 16,0 kw 4,6 l/min 0,0 hrs 48 kw 103 l 3 16,0 kw 4,6 l/min 0,0 hrs 48 kw 0 l 3 16,0 kw 4,6 l/min 0,0 hrs 48 kw 103 l 3 16,0 kw 4,6 l/min 0,0 hrs 48 kw 0 l 3 16,0 kw 4,6 l/min 0,0 hrs 48 kw 103 l 3 16,0 kw 4,6 l/min 0,0 hrs If a 1000l tank with an estimated efficiency of 90% is already in place, the installed heat capacity could be limited to 25kW. It has to be taken care of that the tanks have a heat exchanger capacity of 2.45 kw/ C or about 2.40m²/tank. REQUIRED RE-HEAT POWER FOR A GIVEN TANK Tank Volume of 3th party tank 1000 l Qrh Vtank Qtity Power/tank Flow/tank Re-heat time Nr. of tanks 1 24 kw 1000 l 1 24 kw 13,8 l/min 1,9 hrs Efficiency 0,9 Adviced HEX capacity kj kwh >2,45 kw/ C Etap , >2,40 m²/tank Etank ,325 Ereheat = 43, Possible tap at 43 C without reheat 1364 l This is: heatexchanger capacity = (inlet temp. HEX+outlet temp. Hex)/2-Tank_temperature Example: Manufacturer specifies: 30kW at inlet/outlet = 80 C/60 C and tank temperature = 20 C. => It means heat exchanger capacity = 30/(70-20)=0,6kW/ C This document is for information only and does not constitute an offer binding upon Daikin. Daikin has compiled the content of this document to the best of its knowledge. No express or implied warranty is given for the completeness, accuracy, reliability or fitness for Page28

29 4.5 DHW heating in combination with room heating & cooling. Depending on the system sizing, 1 indoor unit can be connected per tank, or 1 or more indoor units can be connected to several tanks. The below example shows a system that provides DHW, room heating and room cooling with: EMRQ14+(3xEKHVMY80 +1xEKHBRD16 )) = 33.4 kw at Ta=-7 C. (distributed according to the indoor capacity index: 21.1kW by 3xEKHVMYD80, 12.2kW by 1xEKHBRD16). The 21.1kW of the reversible units connected to the 5 tanks will be sufficient for the tapping as shown in example 2 of the DHW sizing (2500l tapping at 43 C in 2 hours. Reheat time will be around 3 hours). During cooling, heat will be recovered for the DHW heating. EMRQ14+3xEKHBRD16. = 35 kw at Ta=-7 C for room heating. As to limit the tap flow per tank, tanks are connected in parallel to the DHW supply. Since only 1 DHW sensor can be connected to 1 indoor unit, tanks are connected according to the Tichelmann principle as to distribute the load equally and this for the DHW connection, the reheat connection and the recirculation connection! The last 2 tanks in above example have no sensor, but temperatures will be the same in all the tanks because equal load distribution. Page29

30 4.6 Dedicated DHW heating with 3th party tank. In dedicated DHW applications, very often big volumes of DHW have to heated. In this case several indoor units can be connected in parallel to 1 or more (field supplied) tanks as shown in the figure below. The standard DHW control of the heat-pump is designed for residential applications, where the amount of DHW to be produced is rather small. It means that the leaving water of the heat-pump in standard domestic hot water mode to heat the tanks is relatively low since it is selected for operation with Daikin tanks, and optimized for efficiency. This can result in capacity shortage when used for commercial applications. For that reason, when using Altherma for dedicated DHW heating, it is strongly advised to use the DHW only settings as explained below, to avoid capacity problems. Page30

31 THE BELOW SETTINGS ONLY APPLY TO EKHBRD*AC MODELS! Parameter settings to be set to put the heat-pump to DHW only mode: [5-04] = 1 [7-01] = 1 The heat-pump can operate up to an ambient of 35 C according to 1 of the configurations below: CONFIGURATION A CONFIGURATION B CONFIGURATION C THERMOSTAT CONTROL By Daikin thermistor By external thermostat Continuous Every unit must be connected with separate Daikin DHW thermistor in the tank. (To be order as spare part if field supplied tank is used: Length=12m) Parameter settings: [6-00] = 1 [6-01] = 0 TEMPERATURE SETTINGS Setting of the DHW parameters on the heat-pump controller(s).- refer to operation manual EKHBRD units: Domestic water heating operation. The leaving water of the heatpump to heat the tank is determined by setting of [F-03]. Target Leaving water will be: SPdhw + [F-03] (SPdhw = setpoint of the domestic hot water). See note below on [F-03]! Every unit must have the optional demand PCB EKRP1AHTA installed. Voltage free contact (from field supplied tank thermostat) must be connected to start operation of the heat-pump Parameter settings: [6-00]=0 [6-01]=1 No setting of the DHW parameters on the controller. Setting of the Leaving Water temperature and ON/OFF differential on the heat-pump controller. SP lwc -[A-02]=H/P Thermo ON SP lwc +[F-00]=H/P Thermo OFF SP lwc = leaving water setpoint. See note below on leaving water setpoint. No Daikin sensor or field supplied thermostat required. Parameter settings: [6-00]=0 [6-01]=0 No setting of the DHW parameters Setting of the Leaving Water temperature and ON/OFF differential on the heat-pump controller. SP lwc -[A-02]=H/P Thermo ON SP lwc +[F-00]=H/P Thermot OFF SP lwc = leaving water setpoint. See note below on leaving water setpoint. AVAILABLE CONTROL FUNCTIONS DHW functions as described Leaving water temperature in installation manual. control functions as described in (reheat, storage, schedule installation manual. (Leaving timer for DHW) water temperature setting, Leaving water temperature ON/OFF, schedule timer for or room temperature control leaving water) NOT available. Leaving water temperature control functions as described in installation manual. (Leaving water temperature setting, ON/OFF, schedule timer for leaving water) Page31

32 Note on F-03 (CONFIGURATION A) Parameter [F-03] (5 C to 25 C, default = 10 C) will determine the temperature difference between the temperature of the water sent to the tank and the tank temperature. The lower this value, the better the SCOP will be (tank is heated with lower temperature), but the lower the heat capacity rejected to the tank will be. Especially, if the tank coil size is rather small, this can cause capacity problems. For this reason, use a tank coil size as advised in 5.3 Requirements for 3th party tank. Note on SP lwc (CONFIGURATION B and C) The setpoint of the leaving water (SP lwc ) must of course be higher than the setpoint of the tank. The lower this value, the better the SCOP will be (tank is heated with lower temperature), but the lower the heat capacity rejected to the tank will be. Especially, if the tank coil size is rather small, this can cause capacity problems. For this reason, use a tank coil size as advised in 5.3 Requirements for 3th party tank. Page32

33 The below figures show a setup according configuration A and B. Configuration A: control with Daikin DHW thermistor Configuration B: Control with external thermostat General: The units are configured for DHW operation and all have 1 DHW sensor attached. The sensors can be located at several heights in the tank. In this way, at small load (only bottom of tank becomes colder) only 1 unit starts up. If load increases, more units will start up. Required additional Daikin options: 1 x DHW sensor per tank. (To be ordered as spare part: Length=12m) Required parameter settings: 5-04 = 1 Activate DHW mode 7-01 = 1 Activate DHW mode 6-00 =1 DHW tank installed F-03 = Temp diff Leaving water with tank temperature(5to25 C) Above settings will: Disable room heating functions (this is the difference with normal DHW mode) Keep enabled all original DHW functions. ( Storage / reheat and disinfection.) Refer to the installation manual of EKHBRD for appropriate settings. Fix the pump speed during operation. (Refer to installation manual of EKHBRD for available ESP) Make sure that, as for normal DHW mode, unit can operate in heating up to 35 C ambient. Control the Leaving water temperature of the heat-pump in function of the actual tank temperature and the target tank temperature. General: The units are configured for heating operation, and are put ON/OFF by an external voltage free contact. In any case, leaving water set-points must be set above the set-point for domestic hot water temperature. Required additional Daikin options: 1 x optional demand PCB EKRP1AHTA per unit. Required parameter settings: 5-04 = 1 Activate DHW mode 7-01 = 1 Activate DHW mode 6-00 = 0 No DHW tank installed 6-01 = 1 External thermostat installed Above settings will: Disable DHW heating functions Enable space heating functions (ON/OFF, Schedule timer, Setpoint for Leaving water). Fix the pump speed during operation. (Refer to installation manual of EKHBRD for available ESP) Make sure, unlike normal space heating mode, that unit can operate in heating up to 35 C ambient. Control the Leaving water temperature of the heat-pump as set on the remote controller. The differential for the leaving water setpoint can be set with parameters A-02 (default value 10 C) and F-00 (default value 5 C) LWT > SP+F-00 Unit thermostat OFF LWT < SP-A-02 Unit thermostat ON Page33

34 5 BI-VALENT APPLICATION 5.1 Reasons to use a bi-valent system From economic point of view, it can be very interesting to design a system as bi-valent. It can cut the initial investment cost drastically, by sizing the heat-pump to a bivalent temperature instead of the design temperature. Moreover, since running hours at the lowest temperatures on yearly base are few, and COP of the heatpump at lowest temperatures is reduced, it will have no or even a positive impact on the running cost. This is clearly illustrated by the below example. DESIGN CONDITIONS Replacement of fuel boiler (75kW load at -6 C) Average heat load : kwh/year Fuel consumption : to l/Year - Fuel Price : 0,82 /l = /kwh /year Average Electricity price : 0.12 /kwh Page34

35 5.2 Hydraulic layout Make sure that the return water to the heat-pump indoor units can never exceed 80 C. For this reason never put the set-point on the boiler above 80 C and install an aquastat valve in the return water flow of the heat-pump unit Boiler located in secondary circuit Boiler with integrated pump Schematic diagram. Operation. The boiler has to be of the modulating type. If not, the balancing bottle at the boiler should be replaced by a storage volume as to avoid excessive cycling of the boiler. Below the bi-valent point, the boiler is released by an ambient thermostat or/and by the backup heater contact of 1 of the heat-pump units. The heat-pump unit to which the boiler is connected should have a set-point of 2 C lower than the other heat-pumps. This will make sure the boiler is only released when the load can t be met by the heat-pump units. The boiler its (weather) dependent set-point should be about 2 C lower than the (weather) dependent setpoint of the heat-pump units as to avoid the heat pumps loading down due to the boiler operation. Page35

36 Wiring diagram. Th1, Th2 : Thermostats P1,P2 : Secondary circuit circulation pumps K1..3A : Auxiliary contacts BS : Boiler Safety MO : Manual operation of boiler In the above example, the control will work as follows: When Th1 closes: - Circulation pump P1 starts and H/P-1 and H/P2 are put ON through their demand PCB EKRP1AHTA (option). When Th2 closes: - Circulation pump P2 starts and H/P-2 and H/P3 are put ON through their demand PCB EKRP1AHTA (option). Only 3 H/P running when both Th1 and Th2 are closed. It is assumed that the load can be covered by 2 heatpumps if only 1 of the 2 secondary pumps is running. Boiler operation is released when: - The manual operation contact is closed - One of the heat-pumps is in alarm. (voltage free contact on EKRP1HBA closes) - There is capacity shortage. Capacity shortage is detected by the backup heater contact of H/P-2, as described below Heater contact step 1 (A3P 14/15) will CLOSE when:all conditions below are met Compressor of H/P 2 has been in operation for more than 20 minutes Compressor of H/P 2 runs just below or at its full frequency Leaving water of H/P2 < SP Cst. T/10*2 (1) Cst = about 5 to 2 depending on model (small model= 5 / big model= 2 T = temperature difference target by pump as set by param A-02 (1) If the leaving water of the H/P is far below its setpoint, i.e. LW < SP Cst. T/5*2; heater contact step 2 will close, without closing step 1 first. See below Heater contact step 2 (A3P 14/16) will CLOSE when all conditions below are met: Heater step 1 has been closed for more than10 minutes Leaving water of H/P2 < SP Cst. T/10*2-1 Return water temperature<sp -. T/ OR Compressor of H/P 2 has been in operation for more than 20 minutes Compressor of H/P 2 runs just below or at its full frequency Leaving water of H/P2 < SP Cst. T/5*2 Heater contact step 2 (A3P 14/16) will OPEN and step 1 will CLOSE when 1 of the conditions below is met: Leaving water of H/P2 > SP Cst. T/10 Return water temperature> SP. T/2-1 Heater contact step 1 (A3P 14/15) will OPEN when 1 of the conditions below is met: Leaving water of H/P2 > SP + 2 NOTE : The backup heater contacts will open when there is request for DHW preparation. For this reason, the heat-pump unit to which the backup heater contact is connected, is preferably not used for the preparation of DHW. Page36

37 Boiler without integrated pump Schematic diagram. Operation. As boiler with integrated pump, but when boiler is released, also the 3 way valve is energized as to send the water of the secondary loop through the boiler Boiler located in the primary circuit When the boiler is put in parallel with the indoor units in the primary circuit, it must be made sure that the units are connected to a low loss collector and decoupling bottle. Otherwise this will cause breakdown because of too low flow in the heat-pumps. In any case, the pressure drop in the primary circuit at maximum flow (all pumps of H/P and boiler running) must be below 7mH20, as to make sure heatpumps have enough flow during operation.. Page37