Air Heat Pump Chiller DT-R(4 Units)

Development of compact air heat pump inverter module chiller

Air heat pump chiller DT-R(4 units)

Takuya ITO Mitsubishi Electric Corporation 1 Biography

• Belonging The Air-conditioning & Refrigeration systems works • Have developed the chiller since 1997 • Planning new product & design

Takuya ITO Mitsubishi Electric Corporation 2 Procedure of presentation

1. Background・Purpose 2. Features of DT-R 3. Energy-saving technology and downsizing technology 4. Simplification of multiple installation construction 5. High efficiency by the multiple module control 6. Conclusions

© Mitsubishi Electric Corporation 1. Background・Purpose (1) Air-cooled heat pump chillers • The chillers are usually used as a central heat source machine for outdoor air processing , air condition or process cooling. • The chillers have been taken notice of effectiveness to prevent global warming to reduce the refrigerant of the indoor unit.

Outdoor unit Air heat exchanger 4 way valve

Refrigerant pipe expansion valve Compressor

Water heat exchanger ACC (Accumulator) Air-cooled heat pump chiller Indoor unit Water pipe Water coil Pump

General air conditioning system(chiller) 4 © Mitsubishi Electric Corporation 1. Background・Purpose

(2) Chiller’s market • A further improvement of performance was requested for both 100% load and part load conditions from the viewpoint of global warming prevention. • A smaller footprint and more capacity is needed.

developed the high efficiency, compact new air-cooled heat pump chiller “DT-R”

© Mitsubishi Electric Corporation 2. Features of DT-R (1) Y-structure The lack of service space is solved between machine rooms by Y-structure. (2) The highest EER in chiller market(2015/10) The EER(50HP 3.47) is achieved by using high performance device of refrigeration circuit. Part load performance is better than conventional machines due to the mounted inverter compressor. (3) High efficiency due to the multiple module control DT-R is designed for high-efficiency operation that can control a number of units during multiple operations. DT-RY -structure"Y型構造" U S X 3 "Xﾌﾚｰﾑ " Performance DT-R Horsepower 60HP 50HP Cooling Capacity(kW) 180 150 EER※1 3.12 3.47 SEER 4.12 4.44 Heating Capacity(kW) 180 150 COP 3.24 3.42 machine Dimension 2,350(H)×1,080(W)×3,400(D) room Refrigerant R410A Capacity per area(kW/m 2) 49.02 40.85 Service space of machine room ※1 Difference of inlet and outlet water temperature is 7 degree celsius the side view (2 connected units) 6 © Mitsubishi Electric Corporation 3. Energy-saving technology and downsizing technology

© Mitsubishi Electric Corporation 3. Energy-saving technology and downsizing technology (1) Air heat exchanger 1) The new slit fin of high heat 2) Large diameter fan transfer rate The flow rate was increased against our The heat transfer rate was improved conventional unit. against our conventional unit by increasing the thermal boundary layer.

Large diameter Air heat fan exchanger The ring fin of our conventional unit

The new slit fin of DT-R (the ZIGZAG slit fin) The new slit fin and large diameter fan 7 © Mitsubishi Electric Corporation 3. Energy-saving technology and downsizing technology

3) High efficiency mounting DT-R was shaped for intake from all four sides by mounting the four L-bend air heat exchangers diagonally downsizing of the unit and to reduce space with multiple installation, Inlet air from four directions Mount diagonally

Air Intake Air discharge Air discharge

Air Air Intake Intake

Air Intake

(a) External (b) Top view (c) Front view 9

(2) dual inverter(High-efficiency scroll compressor and fan motor) 1) inverter compressor The inverter compressor reaches maximum EER when at about 60% capacity. 2) inverter fan motor the flow rate is low → the air heat exchanger cannot function sufficiently. the flow rate is high → fan motor input is increased

DT-R can drive at high efficiency due to rotational speed control for optimum air flow rate in accordance with the operating conditions of the unit.

120% 110%

110% The best air flow rate Scroll compressor 100% 100% (Inverter capacity control) 90%

ratio 90% EER ratio EER 80%

Screw compressor EER 70% (Mechanical capacity control) 80% Input Increase Fan input 60% by high-pressure rise increase

50% 70% 20% 30% 40% 50% 60% 70% 80% 90% 100% 40% 60% 80% 100% 120% Cooling capacity ratio Air flow ratio Comparison of compressor performance Performance to change in air flow rate 10

(2) dual inverter(High-efficiency scroll compressor and fan motor) ･Optimum control of compressor frequency fan rotational speed according to load ･EER ratio 125% (at 55% capacity)

130% Air temp. :35℃ Outlet water temp. :7℃

120% +25% 110% EER ratio EER 100%

90% 40 50 60 70 80 90 100 Cooling capacity ratio(%)

Part load performance of DT-R 11

© Mitsubishi Electric Corporation 3. Energy-saving technology and downsizing technology (3) Two evaporation temperature cycle 1) Independent refrigeration cycle connected in series on the water side 2) Improvement of EER by raising the evaporation temperature

on the upstream side of cold water. 5.0 Upstream 4.5

evap 4.0

- +3.1℃ 4-way valve Compressor 12℃ 3.5 Circuit 2 ) 3.0 +2.2℃ ℃ Circuit 1 ( 2.5 2.0

cycle 1.5 1.0

Evaporation temp. 0.5

difference against 1 0.0 3 4 5 6 7 8 9 10 Difference of water temperature Air heat upon entrance and exit(℃) exchanger 9.5℃ expansion valve Water heat exchanger 104% 2-evap.-cycle 103% Circuit 4 3% Circuit 3 102% 2% 101% 100% 1-evap.-cycle 99% EER ratio 98% 97% 96% 7℃ 3 4 5 6 7 8 9 10 Difference of water temperature Downstream upon entrance and exit(℃) 12 Refrigeration cycle of DT-R © Mitsubishi Electric Corporation 3. Energy-saving technology and downsizing technology

(4) Module coupling structure By connecting the module, DT-R achieved a great reduction of installation space.

Because of the Y-shaped structure, It’s easy for air intake even with consolidated installation.

Y-shaped structure

Side view of 3 connected units

(4) Module coupling structure The installation space was 48% compared with the conventional machine greatly reducing the installation area space requirements. . Installed areas Installed areas 38.5m2(48%) 79.9m2(100%)

1.08 0.9

3.4 0.9 5.2

0.9 0.9

7.4 (a)Development model (b) Conventional model (60HP×5) (100HP×3) Comparison of installation areas 14 © Mitsubishi Electric Corporation 4. Simplification of multiple installation construction

< Selectable water piping specifications> 1.Standard piping can be adopted to and customized for various system. 2.Built-in header establish header pipe connection for each module (collection piping) in the machine room. Piping space can be reduced.

Piping space can be reduced

Standard piping Built-in header 16

It can easily be constructed and shorten the construction period by reducing the connection points and the piping space at the time of multiple installation.

Piping space can be reduced Plumbing connection point

Built-in header The piping inside the module Plumbing at the site (Install at the factory)

Example of built-in header 17

1.Control of each module 空調負荷・Outlet water temperature 空調負荷 constant control ・Optimum control of the number of compressors and frequency and fan rotation speed so that outlet water temperature is constant 2. multiple module control ・determines the number of units Outlet based on the amount of the water compressor frequency of all units.

Remote controller 17

EER ratio at multiple system(60HPｘ4) ･keeping high EER to min-load. ･Determine the optimal number of module.

130% 1-unit 2-unit 3-unit 4-unit 120%

110%

100% Keeping 110%-EER ratio +20％ EER EER ratio 90% 4-UNIT （No number of control） 80% 0% 20% 40% 60% 80% 100% Cooling capactity ratio 20 Comparison of part-load performance of the multiple numbers of controls

The new type chiller DT-R was developed to improve the energy saving and the installation area of air-cooled heat pump chiller.

1. The top level of EER3.47(50HP) and in chiller market was achieved by high performance devices .

2.DT-R has achieved a 48% smaller footprint than conventional machines by the following technology: a) By the New-Y-Shape structure, the modules can connect unit to unit and the space between the modules can be eliminated. b) By using highly-efficient inverter compressors and adopting highly-efficient small air heat exchangers equipped with Zigzag-slit fins, we were able to achieve both high-efficiency and small installation space . c) By using application of highly-efficient 2-evaporation temperature cycles, we were able to achieve the reduction in the water heat exchanger.

We will continue to push further for high efficiency, compact designs and global environment friendly products.

Thank you all very much for your attention.