optimized air/water heat pump selection

OPTIMIZED SELECTION OF A HEAT PUMP FOR THE CITY OF MILAN, USING “SCOPon” APPROACHDipl. Eng. Luca Zordan

Release 06_2014

OPTIMIZED SELECTION OF A HEAT PUMP FOR THE CITY 'OF MILAN, USING “SCOPon” APPROACH

Luca ZordanRelease 06_2014

INTRODUCTION - SCOP

As is known SCOP (Seasonal Coefficient of Performance) describes

the heat pump's average annual efficiency performance.

SCOP is therefore an expression for how efficient a specific heat

pump will be for a given heating demand profile, so in a specific

geographical area.

More precisely, it’s defined two different types of SCOP: SCOPon and

SCOPnet.

Next slides will show the right definition, but take note the first one

(SCOPon) takes into account the contribution - in terms of energy

consumption - of any additional electrical heaters.



INTRODUCTION - Bivalent Temperature

In addition, we have to remember the meaning of «Bivalent

Temperature». The point where the heat pump's capacity

corresponds exactly to the heating demand is known as the bivalent

point. At temperatures below the bivalent point, the heat pump's

capacity has to be supplemented by backup heating. In the SCOP

calculation this is included as pure electric heating with a COP value

of 1, regardless of whether or not the heat pump has an electric

heating element. For higher temperatures the heat pump will run in

part load, which SCOP also takes into account. These conditions are

illustrated in the figure below



INTRODUCTION - Bivalent Temperature

Tdesign T [˚C]

kWPdesign

A (-7˚C) B (2˚C) C (7˚C) D (12˚C)

88%

54%

35%

15%

Tbivalent

Electric Backup

Part load

Capacity



SCOPE

It’s not the purpose of this presentation to explain how to calculate

seasonal coefficients of performance,

BUT THE QUESTIONS ARE:

- considering a given design temperature, it’s better to select a

large heat pump or it’s better a smaller with electrical heater in

addition?

- What is the tool that guides us in an energy-conscious

selection?

I TRIED TO REPLY THESE QUESTIONS INTRODUCING A NEW

APPROACH BASED ON SCOPon.

Enjoy your

reading!


APPLICATION: OFFICE BUILDING

LOCATION:Milan (Italy)


Working Days

SaturdaySunday & holudays

OPERATING TIMES

ON OFF

OPEN

CLOSE


APPLICATION: OFFICE BUILDING


Daytime

Night

Temperature (°C)

Temperature (°C)

Hou

rsU

R %

Annual Operating

Hours Daytime

2670

Hours Night 291

Totale Hours 2961


APPLICATION: HOTEL

LOCATION:Milan (Italy)


Working Days

SaturdaySunday & holudays

OPERATING TIMES

ON OFF

OPEN

CLOSE


APPLICATION: HOTELS


Daytime

Night

Temperature (°C)

Hou

rsU

R %

Temperature (°C)

Annual Operating

Hours Daytime

4116

Hours Night 4116

Totale Hours 8232


CITY OF MILAN

CALCULATION OF SEASONAL PERFORMANCE (SCOPon) WITH

REFERENCE TO UNI EN 14825


Outdoor Temperature

Water temperature supplied

Partial Load Ration (PLR)

Heating Building Capacity

(°C) (°C) % kW TOL -15 45

JDESIGN -5 45 100% 58,0 A -7 45 - 63,5 B 2 45 67% 38,7 C 7 45 43% 24,9 D 12 45 19% 11,0 Tbalance 16 0% 0,0



CITY OF MILAN

SELECTION OF AIR/WATER HEAT PUMP SERIES “BLUE BOX_GEYSER

2 HT”, DEPENDING ON DIFFERENT BIVALENT TEMPERATURE.

It’s been selected No. 5 different bivalent temperatures:

-5°C / -2°C / 0°C / +2°C / +5°C

Resulting in selection No. 5 different sizes of Heat Pump: Geyser 2 HT 90

Geyser 2 HT 70

Geyser 2 HT 60

Geyser 2 HT 50

Geyser 2 HT 32


CITY OF MILAN

SELECTION OF HEAT PUMP SERIES “BLUE BOX_GEYSER 2 HT”

DEPENDING ON BIVALENT TEMPERATURE.


Heating Capacity of Heat Pump

JBIV = -5 JBIV = -2 JBIV = 0 JBIV = 2 JBIV = 5

Geyser 2 HT 90 Geyser 2 HT 70 Geyser 2 HT 60 Geyser 2 HT 50 Geyser 2 HT 32

[kW]PTOL [kW] 48,9 36,5 32,0 27,3 19,6

COPTOL 2,36 2,22 2,29 2,36 2,20PBIV [kW] 60,5 48,4 44,4 38,4 29,5COPBIV 2,84 2,90 3,11 3,21 3,35PA [kW] 58,1 43,7 38,4 32,2 23,4

COPBIV,A 2,75 2,62 2,71 2,74 2,63PB [kW] 70,0 52,4 46,2 38,4 27,9

COPBIV,B 3,24 3,14 3,24 3,21 3,16PC [kW] 77,4 57,7 51,1 42,3 30,7

COPBIV,C 3,57 3,47 3,58 3,53 3,50PD [kW] 85,5 63,3 56,3 46,5 33,6

COPBIV,D 3,92 3,84 3,95 3,82 3,84


SCOPon: DEFINITION



CITY OF MILAN

CALCULATION OF “SCOPon” (Bin-method, Cfr. EN 14825)



CITY OF MILAN

CALCULATION OF “SCOPon” FOR EACH HEAT PUMP SIZE


Annual Heating demand of the building

Annual Heat Pump Capacity

Annual power input with electrical heater

Annual power input without electrical heater

Annual Heating demand of the building

Annual Heat Pump Capacity

Annual power input with electrical heater

Annual power input without electrical heater

kWh kWh kWh kWh kWh kWh kWh kWh35.427 35.427 12.584 12.584 54.368 54.368 19.306 19.306

SCOPon SCOPnet SCOPon SCOPnet

2,82 2,82 2,82 2,82

35.427 35.331 12.161 12.065 54.368 54.260 18.620 18.512


2,91 2,93 2,92 2,93

35.427 34.922 11.810 11.306 54.368 53.745 18.001 17.378


3,00 3,09 3,02 3,09

35.427 33.942 12.292 10.807 54.368 52.313 18.691 16.636


2,88 3,14 2,91 3,14

35.427 30.255 14.522 9.350 54.368 46.746 22.044 14.422


2,44 3,24 2,47 3,24

UFFICI HOTELOFFICE BUILDING

HOTEL

ITEM 1

ITEM 2

ITEM 3

ITEM 4

ITEM 5



CITY OF MILAN - RESULT

-5 -2 0 2 51

3

5

7

9

11

13

15

2.82 2.91 3.00 2.882.44

Annual Power Input with Electrical heater and SCOPon

Annual Power Input with Elect heater SCOP_on

MW

h/ye

ar

• Point of Minimum Energy

consumption

• Point of Maximum SCOPon

value

Application : OFFICE BUILGING



MAIN RESULT

Applying this analytical “SCOPon” approach, with reference to

the obtained datas it is clear that the selection energetically

more convenient is on model GEYSER 2 HT 60, in

correspondence of a bivalent temperature Tbiv = 0°C



CITY OF MILAN – COMBINED RESULTS: OFFICE BUILDING &

HOTEL



MAIN NOTE

This is an analytical method that could be applied to optimize

the heat pump selection. However, it’s essentially defined for

winter heating. In the Italy area, the application of the reversible

heat pump (for combined use in summer and winter) is much

preferred and used in respect to "just heating" applications.

The strong sensible and latent loads in our "beautiful country"

during summer, heavily influence the selection of the size of the

unit.



THANKS FOR YOUR ATTENTION

[email protected]

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