Optimized Scroll Compressor

for Green Heat Pump Unit

in Retrofit Buildings

Grant Agreement No 308816

FP7-Energy-2012-308816 www.greenhp.eu

Bachir.Bella@emerson.com

The GreenHP Partners

Austrian Institute of Technology,

Project Coordinator

Fraunhofer Insitute for Solar

Energy Systems, Germany

Royal Institute of Technology,

Sweden

European Heat Pump Association,

Belgium

Hesch Schröder GmbH, Germany

Emerson Climate Technologies

GmbH, Germany

AKG Group, Germany

Ziehl-Abegg, Germany

Gränges AB, Sweden

FP7-Energy-2012-308816

Project Info Description: The GreenHP project investigates a new highly efficient heating

system based on high-capacity air/water heat pumps for retrofitting multi-family

houses and commercial buildings in cities.

Targets: The project aims at developing a new system level (interaction with

electric grids, other energy systems and different system components) as well as a

new heat pump unit and component units (refrigerant, compressor, evaporator, fan

and air duct, condenser)

FP7-Energy-2012-308816

Application Heat Pump Unit for large retrofitting buildings in average climate

System: Air/water output up to 100 kW

High Efficiency Prototype Heating capacity 30kW at (A -10/W 55)

Capable of water heating up to 65°C

COP (A7/W55) ≥ 3.5

SCOP* ≥ 3.1

Low GWP refrigerant with Charge target 1 kg GWP < 150

High Efficiency

Reduced Oil charge in the compressor

Air/Water and Water/Water Heat Pump Radiators & Underfloor Heat Distribution

• A/C Scroll: ZR/ZP

• Heating Scroll: ZH**K4E

• Heating Scroll EVI: ZH**KVE

A/W Unit for retrofit require both:

High condensing temperature

Low evaporating temperature

Compressor Design Scroll Design

30 kW Maximum Heating Load at A-10/W55 (-18 °C Evap./58°C Cond.) determines a

Displacement of 96 cc

Optimization elaborated for average climate

0

2

4

6

8

10

12

0

500

1000

1500

2000

2500

3000

-10 -5 0 5 10 15 20

Wo

rkin

g P

res

su

re R

ati

o

En

erg

y (k

Wh

)

Ambient Temp. ( C)

Opt.

Vi Compression Start

Vf Compression End

Heating Energy weighted to operation hours according to EN14825

Compressor working pressure ratio varying with ambient Temperature:

Pressure ratio P.R. = 3.6 results in Optimized BIVR design for SCOP

Compressor Design DC motor Variable Speed

More efficient over a large speed range

Some efficiency decrease at full load

related to inverter losses

Requires special design consideration:

Inverter generates electro-magnetic

interference (EMI)

Necessitates piping circuits to

ensure Oil return

Requires special consideration to

avoid resonances

Oil delivery required for speeds

less than 2400 rpm

DC Motor with higher Efficiency over a wide range

Speed range 1800-7200rpm (30-120Hz)

h%

rpm

Permanent Magnet Motor

DC motor

AC standard motor

2.8

3.1

3.7

2

2.5

3

3.5

4

Fixed speed Fixed Speed EVI Variable Speed EVI

SC

OP

SCOP - Simulation (W55)

12%

17%

Compressor Design Variable Speed and EVI Benefits for SCOP

• EVI (Enhanced Vapour Injection)

Gives +12% SCOP

• with Variable Speed another +17%

SCOP

• (Variable Speed) + (EVI Scroll) give

an increase of +30% in SCOP

EVI Effect VS Effect

Simulation elaborated with R410A

Compressor Design Oil Charge Reduction

Oil charged inside the compressor depends:

Internal oil management inside compressor

Amount mixed with refrigerant and circulating inside the system

GHP compressor targeting 1.0 liter (Similar size standard Scroll have 2.5 liters)

ZHW0961U New design to decrease oil level:

Lower bearing designed to the lowest position inside the shell

Optimize Suction gas port position to decrease the oil pump out from the compressor

Minimum oil required is 1 liter, higher charge will be only for system management

Oil Charge Reduction Impact on Refrigerant Charge

The refrigerant diluted varies with the

operating conditions:

Higher the evaporating temp., higher

is the oil mass diluted

Lower the evaporating temp., lower is

the oil mass diluted

Lower is the gas return temperature

higher is the oil mass diluted

25/40°C 0/56°C -18/58°C Oil Reduction

(g) (g) (g) (%)

2.5 l 258 83 44 -

1.5 l 155 50 27 -40%

1.0 l 103 33 18 -60%

Oil Charge

Refrigerant Diluted in Oil

41

91

258

235

15147

3351

102

162

0

20

40

60

80

-35 -25 -15 -5 5 15 25 35

Co

nd

en

sin

g T

em

pe

ratu

re ( C

)

Evaporating Temperature ( C)

R290 Dilution in the Oil Sump (g)

1.5 liters oil sump

28 91

20

2454

141

155

2.5 liters oil sump

Refrigerant decreases from 83 g to 33 g at rating Conditions (0/56°C)

Maximum R290 diluted 155 g w/ 1.5 liters and 103 g w/ 1.0 liter

ZHW096 Performances

0.00

1.00

2.00

3.00

4.00

5.00

0

10

20

30

40

50

1000 3000 5000 7000 9000

He

at.

CO

P (

-)

He

ati

ng

Ca

pa

cit

y (

kW

)

Speed (rpm)

ZHW096 (GHP)

Comp. Cond. Target Achiev.

Max Heating Capacity (-18/58°C) 30 kW 28.2 kW

COP (A7/W55) (0/56°C) 3.50 3.50

SCOP (EN14825) Avg. Climate 3.1 3.3

Heating capacity and COP

calculated according to EN14825

average climate and based on

compressor performances

R290 allows to reach extreme conditions

10

20

30

40

50

60

70

80

-35 -25 -15 -5 5 15 25 35

Co

nd

. T

em

pe

ratu

re ( C

)

Evap. Temperature ( C)

Heating Range

R290

R410A

R407C

Heating

Variable Speed Scroll

• Range 1800 – 7200rpm

• BPM motor

• High Efficiency

• Drive 18.5kW

• Modbus comunication

R290 Solution

Scroll

EVI

Flow Controls

Scroll

Variable

Speed

Overview Package R290 Solution

Vapor injection Scroll

• Swept volume 96cc

• 30 kW Heating @ -18/58C

• HCOP (A7/W55) = 3.5

• Oil charge ≤ 1.5 liters

System Flow Controls

• Electronic Ref control module

• Refrigerant Circuit controller

• Electronic Alco Exp. Valve

Main Evap SH 4-way valve Actuator

RCC

Main System Control Hesch

Economizer SH

Conclusions

New compressor design developped for GHP Unit

Design Optimized to meet GHP Targets:

Optimized Scroll Design

Variable Speed Technology with BPM motor

Oil Charge Reduction

Results:

Combination R290 and Vapor Injection allow high water temperature at

extreme conditions (Retrofit heating system)

Compressor High Efficiency (SCOP =3.3, HCOP (A7/W55) = 3.50)

Oil charge Reduction by at least 40%

Thank you for your Attention !

Contact Project Coordination

ANDREAS ZOTTL

Engineer

Energy Department

Sustainable Thermal Energy Systems

AIT Austrian Institute of Technology GmbH

Giefinggasse 2 | 1210 Vienna | Austria

T +43(0) 50550-6309 | F +43(0) 50550-6679

andreas.zottl@ait.ac.at | http://www.ait.ac.at

FP7-Energy-2012-308816