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of 18 Version 2.0

D4.2. /D 2.4. Concept for evaluation of SPF

Version 2.2 A defined methodology for calculation of the seasonal performance

factor and a definition which devices of the system have to be

included in this calculation.

Heat pumps with hydronic heating systems

Date of delivery: 2012-05-31

Contract No.:

IEE/08/776/SI2.529222

Authors:

Andreas Zottl, AIT

Roger Nordman, SP

Co-Authors

Michel Coevoet, Edf

Philippe Riviere, Armines

Marek Miara, ISE Frauenhofer

Anastasia Benou, CRES

Peter Riederer, CSTB

The sole responsibility for the content of this document lies with the authors. It does not necessarily reflect the opinion of the European

Communities. The European Commission is not responsible for any use that may be made of the information contained therein.

of 18 Version 2.0

Content

FOREWORD ......................................................................................................................................................... 3

NOMENCLATURE .............................................................................................................................................. 3

SEASONAL PERFORMANCE FACTOR (SPF) EVALUATION .................................................................. 4

SYSTEM BOUNDARY DESCRIPTION ...................................................................................................................... 4 SYSTEM BOUNDARIES – HEATING MODE:............................................................................................................. 5

SPF-calculation – heating mode: .................................................................................................................. 6 SYSTEM BOUNDARIES – COOLING MODE: ............................................................................................................ 8

SPF calculation – cooling mode: .................................................................................................................. 9 SPF calculation – simultaneous cooling and heating mode: ....................................................................... 10

OPERATING MODES ....................................................................................................................................... 11

SPACE HEATING ................................................................................................................................................ 11 DOMOSTIC HOT WATER ..................................................................................................................................... 11 COOLING ........................................................................................................................................................... 11 DEFROST MODE ................................................................................................................................................. 11

Direct electric defrosting ............................................................................................................................. 12 Hot gas defrosting ....................................................................................................................................... 12 Reverse cycle defrosting .............................................................................................................................. 12

COMPARISON OF THE SYSTEM- BOUNDARIES IN STANDARDS AND THE SYSTEM –

BOUNDARIES OF THE SPF-CALCULATION METHODOLOGY ........................................................... 13

LITERATURE .................................................................................................................................................... 16

ANNEX – CALCULATION EXAMPLE .......................................................................................................... 17

EXAMPLE-A HEAT PUMP WITH ELECTRIC BACK UP ............................................................................................ 17 EXAMPLE-B HEAT PUMP WITH ADDITIONAL GAS HEATING ................................................................................ 18

D4.2. Concept for evaluation of SPF

page 3 of 18 Version 2.0

Foreword

The aim of this document is to define the system boundaries for calculating the SPF for

heating and cooling of heat pump systems. Defining the system boundaries has direct impact

on the necessary measurement equipment to measure the needed parameters for the

calculation of the different SPF. For this reason the document should be revised after the first

measurement period to see if the defined system boundaries can be measured in the field or if

there have to be some adoptions.

Nomenclature

Q C produced cooling energy of the CU for cooling [kWh]

E S_fan/pump electrical energy use of the CU- heat sink: fan or brine/well pump [kWh]

E B_fan/pump electrical energy use of the building fans or pumps [kWh]

E CU electrical energy use of the CU [kWh]

E bt_pump electrical energy use of the buffer tank pump [kWh]

SH space heating [-]

DHW domestic hot water [-]

HP heat pump [-]

CU Cooling unit [-]

SPF i Seasonal performance factor (Index: H for heating, C for cooling) [-]

COP Coefficient of performance [-]

EER Energy efficiency ratio [-]

SEER Seasonal energy efficiency ratio [-]

For heating mode:

Q H_hp quantity of heat of the HP in SH operation [kWh]

Q W_hp quantity of heat of the HP in DHW operation [kWh]

Q HW_bu quantity of heat of the back-up heater for SH and DHW [kWh]

E S_fan/pump electrical energy use of the HP source: fan or brine/well pump for

SH and DHW

[kWh]

E B_fan/pump electrical energy use of the heat sink (building): fans or pumps for

SH and DHW

[kWh]

E bt_pump electrical energy use of the buffer tank pump [kWh]

E HW_hp electrical energy use of the HP for SH and DHW [kWh]

E HW_bu energy use* of the back-up heater for SH and DHW [kWh]

*for additional heating other then electrical back up heater the energy content of

the fuel demand has to be taken

For cooling mode:



Seasonal Performance Factor (SPF) evaluation

D4.2.-“Concept for evaluation of SPF” describes a standard evaluation method for monitoring

results to get data for quality characteristics for heat pump systems and technologies. This

SPF calculation method also provides the possibility to include the impact of auxiliary devices

like brine pumps and fans on the performance of the heat pump system, which will be taken

into account by the definition of different system boundaries.

The methodology of calculating the SPF makes it possible to compare the heat pump system

with common heating systems like oil or gas. By this comparison it is also possible to

calculate the CO2- and primary energy reduction potential from different heat pump systems

compared to other heating systems.

This evaluation method is based on a harmonised monitoring methodology, also developed in

the “SEPEMO” project, which allows disposing all necessary measurement data for applying

the evaluation method presented in this document.

System boundary description

The definition of the system boundaries influences the results of the SPF depending on the

impact of the auxiliary drives. Therefore the SPF should be calculated according to different

system boundaries. This will reflect the impact of the different devices on the performance of

the system.

Due to the fact that the units can operate in heating and/or cooling mode the system

boundaries and the SPF-calculation methodology is separated for heating and cooling mode.

According the described system boundaries the SPF can be calculated for cooling, space

heating and domestic hot water production.

For systems with an additional heating system other than an electrical back up heater (e.g. oil,

gas or biomass) the quantity of heat and the energy content of the fuel demand have to be

determined for calculating SPFH3 and SPFH4. The energy content can be determined by

measuring the fuel demand and multiplying with the calorific value of the fuel. For additional

solar thermal systems the electric auxiliary energy to run the system has to be measured.

With the heat energy delivered to the heating system by the additional heating the energy

supply ratio of the heat pump system is calculated.

The following definitions of the system boundaries are a general description for all different

heating and cooling systems considered in the project SEPEMO. Therefore the possibility to

realise the measurement can be slightly different for the different systems, but it is possible to

have correct comparisons within the different systems e.g. Air/Water with another Air/Water

system. For technical reasons Air/Air systems can only be measured and analysed according

to SPFH3 / SPFH4 and SPFC3.



System boundaries – heating mode:

SPFH1:

This system contains only the heat pump unit. SPFH1 evaluate the performance of the

refrigeration cycle. The system boundaries are similar to COP defined in EN 14511 [1],

except that the standard takes, in addition, a small part of the pump consumption to overcome

head losses, and most part of fan consumption.

SPFH2:

This system contains of the heat pump unit and the equipment to make the source energy

available for the heat pump. SPFH2 evaluate the performance of the HP operation, and this

level of system boundary responds to SCOPNET in prEN 14825 [2] and the RES-Directive [3]

requirements1.

Note: COP in EN 14511 and SCOPNET in prEN 14825 are more or less between SPFH1 and

SPFH2 (see table 1 at the end of the document)

SPFH3:

This system contains of the heat pump unit, the equipment to make the source energy

available and the back up heater. SPFH3 represents the heat pump system and thereby it can be

used for comparison to conventional heating systems (e.g. oil, gas,…). This system boundary

is similar to the SPF in VDI 4650-1 [4], EN 15316-4-2 [5] and the SCOPON in prEN 14825.

For monovalent2 heat pump systems SPFH3 and SPFH2 are identical.

SPFH4:

This system contains of the heat pump unit, the equipment to make the source energy

available, the back up heater and all auxiliary drives including the auxiliary of the heat sink

system. SPFH4 represents the heat pump heating system including all auxiliary drives which

are installed in the heating system.

space

heatig buffer

tank

hot

water

tank

heat

pump

SPFH1

SPFH2

SPFH3

SPFH4

Figure 1: Example scheme for a heating system

1 For compact heat pumps having built-in electric backup heaters, this would constitute a problem, since the SPF

is normally attributed the product, and then SPFH3 is easier to evaluate in praqctice.. 2 Monovalent heat pumps are heat pumps without supplemental (backup) heating.



SPF-calculation – heating mode:

In this chapter the formulas for calculating the SPF for heating mode together with the energy

flowcharts for the different system boundaries are described.

heat pump

heat

source

fan or pump

Back-up

heater

bu

ildin

g fa

ns o

r p

um

ps

SPFH1

SPFH2

SPFH3

SPFH4

QH_hp

QW_hp

QHW_bu

EB_fan/pumpEHW_buEbt_pumpEHW_hpES_fan/pump

Figure 2: energy flow chart for the heating mode

hpHW

hpWhpH

HE

QQSPF

_

__

1

hpHWpumpfanS

hpWhpH

HEE

QQSPF

_/_

__

2

buHWhpHWpumpfanS

buHWhpWhpH

HEEE

QQQSPF

__/_

___

3

heat pumpheat

source

SPFH1 QH_hp

QW_hp

EHW_hp

heat pump

heat

source

fan or pump

SPFH2 QH_hp

QW_hp

EHW_hpES_fan/pump

heat pump

heat

source

fan or pump

Back-up

heater

SPFH3 QH_hp

QW_hp

QHW_bu

EHW_buEHW_hpES_fan/pump



pumpfanBbuHWpumpbthpHWpumpfanS

buHWhpWhpH

HEEEEE

QQQSPF

/____/_

___

4

heat pump

heat

source

fan or pump

Back-up

heater

SPFH4

bu

ildin

g fa

ns o

r p

um

ps

QH_hp

QW_hp

QHW_bu

EB_fan/pumpEHW_buEbt_pumpEHW_hpES_fan/pump



System boundaries – cooling mode:

SPFC1:

This system contains only the cooling unit. SPFC1 evaluate the performance of the

refrigeration cycle. The system boundaries are similar to EER defined in EN 14511 [1],

except that the standard takes, in addition, a small part of the pump consumption to overcome

head losses, and most part of fan consumption.

SPFC2:

This system contains the cooling unit and the equipment to dissipate the heat energy. The

system boundaries compares to SEERON in prEN 14825 [2].

Note: EER in EN 14511 and SEERON in prEN 14825 are more or less between SPFC1 and

SPFC2 (see table 1 at the end of the document)

SPFC3:

This system contains the cooling unit, the equipment to dissipate the heat energy and all

auxiliary drives of the cooling system. SPFC3 represents the cooling system including all

auxiliary drives which are installed in the cooling system.

SPFC4:

This system contains the cooling studied cooling system and possible additional cooling

systems. In this analysis it is assumed that additional, supplementary, cooling systems are

autonomous from the studied system. This level corresponds to the total cooling system

performance for a building.

space

cooling

buffercooling

unit

SPFC3

SPFC2

SPFC1

Supplementary

cooling unit

SPFC4

Figure 3: Example scheme for a cooling system



SPF calculation – cooling mode:

In this chapter the formulas for calculating the SPF for cooling mode together with the energy

flowcharts for the different system boundaries are described.

cooling

unitfan or pump

bu

ildin

g fa

ns o

r p

um

psheat

sink

SPFC1

SPFC2

SPFC3

ES_fan/pump ECU Ebt_pump EB_fan/pump

Supplementary

cooling unit

QC

QC_BU

SPFC4

EC_BU

Figure 4: energy flow chart for the cooling mode

CU

C

CE

QSPF 1

CUpumpfanS

C

CEE

QSPF

/_

2

cooling

unitQC

heat

sink

SPFC1

ECU

cooling

unitfan or pump

SPFC2

ECUES_fan/pump

QC

heat

sink



pumpfanBpumpbtCUpumpfanS

C

CEEEE

QSPF

/__/_

3

BUCpumpfanBpumpbtCUpumpfanS

BUCC

CEEEEE

QQSPF

_/__/_

_

4

cooling

unitfan or pump

bu

ildin

g fa

ns o

r p

um

psheat

sink

SPFC1

SPFC2

SPFC3


Supplementary

cooling unit

QC

QC_BU

SPFC4

EC_BU

SPF calculation – simultaneous cooling and heating mode:

For systems operating simultaneously in cooling and heating mode, e.g. for domestic hot

water production, the fraction of heat delivered to the system has to be taken into account

when calculating the different combined SPF according to the system boundaries.

cooling

unitfan or pump

bu

ildin

g fa

ns o

r p

um

ps

SPFC3

heat

sink

QC




Operating modes

The heating and cooling systems can be operated in different modes. The most common

operating modes for combined systems can be defined as:

space heating and domestic hot water operation

cooling and domestic hot water operation

space heating, cooling and domestic hot water operation

Therefore the heat meters or flow meters and temperature sensors have to be integrated into

the system as described in deliverable D4.1 - guideline for heat pump field measurements, to

be able to evaluate the system efficiency according to the different system boundaries and

depending on the operating modes.

Especially for Air to water systems the defrost mode has to be considered when calculating

the SPF.

Space heating

The system is operating in this mode to provide heat to the heating distribution system.

Domostic hot water

The system will operate in this mode to provide heat to the domestic hot water tank.

For monobloc/compact heat pumps supplying space heating and domestic hot water, it is

often due to practical reasons not possible to separate measurements of the heat delivered to

space heating and to domestic hot water. In these cases the useful energy supplied by the heat

pump can be identified in two ways:

1. By monitoring the total heat generated by the heat pump before the three-way valve

2. By monitoring the space heat output from the heat pump and to monitor the hot water

consumed by the end user (flow and temperature), and to correct the useful energy by

tank losses (based on lab measurements or calculations).

The first option is the more accurate method, but needs intrusive measurements in the heat

pump, which are costly and could affect end user guarantees. The second option is based on

extremely good precision of the hot water measurements, and the use of either experience

values or mathematical models for assessing the DHW tank losses. Depending on the

installation location (living space or technical room) the useful energy can be calculated for

space heating.

Cooling

The system will operate in this mode to cool the building.

Defrost mode

Air to water heat pump systems have to be operated in defrost mode for deiceing the

evaporator in winter time when the air humidity causes icing of the out door heat exchanger.

There are different possibilities for defrosting, the 3 most common strategies are:

Direct electric defrosting

Hot gas defrosting

Reverce cycle defrosting



Direct electric defrosting

For calculating the SPF (Figure 5), the additional electrical energy demand for operating the

defrost heating has to be added. As described in the chapter “system boundaries” the electric

energy demand for defrosting should be a part of EHW_hp.

Figure 5: direct electric defrosting

Hot gas defrosting

When calculating the SPF for systems with hot gas defrosting (Figure 6) no additional

measurement and calculation is necessary. The used hot gas for defrosting will decrease the

heating capacity of the system, which will be recorded by the heat meter.

Figure 6: hot gas defrosting

Reverse cycle defrosting

Systems with reverse cycle defrosting will extract heat from the heating system during defrost

operation. This heat is not usable for the heating distrubtion system and has to be subtracted

form the heat delivered to the system when calculating the SPF. As described in Figure 7 it

has to be differentiated between the heat out put of the heat pump (Qhp) and the useful heat

delivered to the building by the heat pump (Qhp-useable).

hp

hp

E

QSPF

defelechp

hp

EE

QSPF

_



Figure 7: reverse cycle defrosting

Comparison of the system- boundaries in standards and the

system – boundaries of the SPF-calculation methodology

There are different existing standards and regulations for calculating the SPF. These

calculation methodologies are mainly based on input from the testing standard EN 14511. The

system boundaries of testing standards are however focused on the heating or cooling unit

itself. For comparing test results of the units with other units, the system integration is not

taken into account. Therefore these standards do not include the entire energy consumption of

the auxiliary drives on the heat sink and heat source side. The following descriptions show the

differences between the system boundaries for field measurements and testing standards. The

aim is to point out the difference between field testing and testing on a test rig, which does not

necessarily mean that there should be no differences as this is not possible for practicable

measurement systems in the field. The main difference of the evaluation methodologies is that

testing is focused on the unit and the field measurements are focused on the system. For field

measurements measuring the proportional energy input on the heat sink and heat source side

requires high efforts for the measurement equipment and can not be realized within the

common field measurement methodology.

Hence the system boundaries for testing and field measurements will be slightly different, this

has to be a taken into account when comparing calculated SPF and measured SPF.

EN 14511: This standard describes the testing procedure to calculate the COP or EER. The

average electrical power input of the unit within the defined interval of time is obtained from:

the power input for operation of the compressor and any power input for defrosting;

the power input for all control and safety devices of the unit and;

the proportional power input of the conveying devices (e.g. fans, pumps) for ensuring

the transport of the heat transfer media inside the unit.

This equates to the system boundary of SPFH1/SPFC1, with the difference being, that

SPFH1/SPFC1 does not include the proportional energy input of the auxiliary devices.

EN 15316 4-2: This standard describes a calculation Bin method for energy consumption,

starting from, among other, heating load evolution, heating curve of the heat pump, climate

conditions and standard heat pump testing points. This method standardizes boundary

contains the heat pump unit, the equipment to make the source energy available, internal and

external boilers and back-up heaters. This equates to boundary SPFH4. The difference is that

hp

defhphp

E

QQSPF

_



SPFH4 include the buffer tank pump that supplies water to the SH water circuit and that in the

standard EN 15316-4-2 the thermal losses of the heating system are calculated.

Figure 8: system boundary EN 15316-4-2

prEN 14825:

The calculation methodology and the measurement procedure of this standard are based on

the standard EN 14511. Therefore the auxiliary drives are mentioned partly in the SCOP

calculation. SCOPNET is more or less similar to SPFH2 and SCOPON/SEERON to SPFH3/SPFC2.

prEN 14825 makes a difference between SCOPON / SEERON and SCOP / SEER as they

exclude electricity consumption of thermostat off mode, stand-by modes or crankcase heater.

Unlikely EN 15316-4-2, different running conditions are set, according climate (3 zones: cold,

average, warm) and space heating emitters, what gives SCOP/SEER for heat pump whose

features are known at 6 tested conditions.

European Directive 2009/125/EC Lot 1:

Calculation of energy consumption in Lot 1 is quite similar to prEN 14825, except that heat

demand included more items in addition to heat load, like buffer heat losses and distribution

heat losses as it is mentioned in the EN 15316-4-2.

Lot 10:

Similar to prEN 14825

VDI 4650-1: The SPF calculation according to this regulation includes the heat source

auxiliary drives, the back up heater and the auxiliary drive energy for space heating (for



pressure losses of the condenser) as mentioned in the EN 14511. This equates to the system

boundary of SPFH3, but the difference is the proportional energy input of the auxiliary devices

on the heat sink side.

The following table 1 gives an overview of the difference between the defined system

boundaries for evaluating the measurement data and existing standards.

Component SP

FH

1/C

1

SP

FH

2/C

2

SP

FH

3

SP

FH

4/C

3

EN

14

51

1

EN

15

31

6 4

-2

VD

I46

50

-1

prE

N1

48

25

*

Lo

t 1

Lo

t 1

0

Compressor x x x x x x x x x x

Brine

fan/pump --- x x x

head

losses x x

head

losses

head

losses

head

losses

Back-up --- --- x x --- x x x x x

Buffer tank

pump --- --- --- x --- x --- --- x ---

SH DHW

fans/pumps --- --- --- x

head

losses X**

head

losses

head

losses

head

losses

head

losses *refers to SCOP and SEER

**see figure 5 (system boundary EN 15316-4-2)

Table 1: comparison of system boundaries



Literature

[1] EN 14511, Air conditioners, liquid chilling packages and heat pumps with electrically

driven compressors for space heating and cooling, March 2008

[2] prEN 14825, Air conditioners, liquid chilling packages and heat pumps, with electrically

compressors, for space heating and cooling- Testing and rating at part load conditions and

calculation of seasonal performance, November 2009

[3] RES Directive, DIRECTIVE 2009/28/EC OF THE EUROPEAN PARLIAMENT AND

OF THE COUNCIL, April 2009

[4] VDI 4650-1, Calculation of heat pumps Simplified method for the calculation of the

seasonal performance factor of heat pumps Electric heat pumps for space heating and

domestic hot water, March 2009

[5] EN 15316-4-2, Heating systems in buildings – Method for calculation of system energy

requirements and system efficiencies – Part 4-2: Space heating generation systems, heat pump

systems, September 2008



Annex – calculation example

Example-A: heat pump with energy supply ratio of 94 %

hpHW

hpWhpH

HE

QQSPF

_

__

1

buHWhpHWpumpfanS

buHWhpWhpH

HEEE

QQQSPF

__/_

___

3

hpHWpumpfanS

hpWhpH

HEE

QQSPF

_/_

__

2

pumpfanBbuHWhpHWpumpfanS

buHWhpWhpH

HEEEE

QQQSPF

/___/_

___

4

additional

electric heating

additional gas

heating

additional solar

heating

SPFH1 - 5,0 5,0 5,0

SPFH2 - 4,3 4,3 4,3

SPFH3 - 3,6 3,4 4,5

SPFH4 - 3,3 3,2 4,2

additional

electric heating

additional gas

heating

additional solar

heating

Q H_hp [kWh] 12000 12000 12000

Q W_hp [kWh] 3000 3000 3000

Q HW_bu [kWh] 1000 1000* 1000

E S_fan/pump [kWh] 500 500 500

E B_fan/pump [kWh] 300 300 300

E HW_hp [kWh] 3000 3000 3000

E HW_bu

[kWh] 1000 1176** 25***

* efficiency gas boiler 85

%

** measured fuel demand

121 m³ gas, calorific heat

of gas 9,7 kWh/m³

*** electric energy demand

of the circulating pump in

the solar system



Example-B: heat pump with energy supply ratio of 66 %

hpHW

hpWhpH

HE

QQSPF

_

__

1

buHWhpHWpumpfanS

buHWhpWhpH

HEEE

QQQSPF

__/_

___

3

hpHWpumpfanS

hpWhpH

HEE

QQSPF

_/_

__

2

pumpfanBbuHWhpHWpumpfanS

buHWhpWhpH

HEEEE

QQQSPF

/___/_

___

4

additional

electric heating

additional gas

heating

additional solar

heating

SPFH1 - 5,0 5,0 5,0

SPFH2 - 4,3 4,3 4,3

SPFH3 - 2,0 1,8 6,2

SPFH4 - 1,9 1,7 5,5

additional

electric heating

additional gas

heating

additional solar

heating

Q H_hp [kWh] 9000 9000 9000

Q W_hp [kWh] 1500 1500 1500

Q HW_bu [kWh] 5500 5500* 5500

E S_fan/pump [kWh] 350 350 350

E B_fan/pump [kWh] 300 300 300

E HW_hp [kWh] 2100 2100 2100

E HW_bu

[kWh] 5500 6471** 140***

* efficiency gas boiler 85

% ** measured fuel demand

667 m³ gas, calorific heat of gas 9,7 kWh/m³

*** electric energy demand

of the circulating pump in the solar system

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