Smart Cooling TechniquesLow Energy approach

Different techniques.

Physics

Thermo Active Building Systems.

The reason.

Radiant Floors.

BANK OF BHUTAN(BOB)

APPROXIMATE COMPARISON BETWEEN WATER COOLED CHILLER AND VRV SYSTEM

DATE:20/03/2013

S.NOS. DESCRIPTION WATER COOLED CHILLER(TR) VRV SYSTEM (HP)

ASSUMED AIR CONDITIONING AREA 75000 SQFT 75000 SQFT

1 APPROX.TOTAL INSTALLED CAPACITY IN THE BANK 325 450

2 OPREATIONAL CAPACITY @85 % OF THE TOTAL CAPACITY INSTALLED 275 380

3 OPREATIONAL HOURS IN A DAY 8 8

4 POWER CONSUMPTION PER UNIT AT MAXIMUM TEMP.IN BHUTAN 1.3 0.9

5 POWER CONSUMPTION PER HOUR/UNIT (KWH) IN INDIAN RUPEES 8 8

6 ASSUMED NOS OF WORKING DAYS IN ONE YEAR IN BANK 300 300

7 TOTAL NOS OF OPREATION HOURS IN ONE YEAR 2400 2400

8 TOTAL OPREATIONAL COST PER YEAR OF SYSTEM 6864000 6566400

9 ESTIMATED CAPITAL COST OF THE SYSTEM 74651400 69496900

10 DIFFERENCE IN CAPITAL COST *(CHW-VRV SYSTEM) -5154500

11 DIFFERENCE IN OPREATIONAL COST PER YEAR*(CHW-VRV SYSTEM) -297600

CHW vs VRV System Comparison.

SYSTEMS CHW vs VRVS.No. FEATURE VRV SYSTEMS WATER COOLED CHILLER SYSTEMS REMARKS

1 Type of System Completely AIR-COOLED SYSTEM with three basic parts-

Outdoor, indoor units & controllers

WATER COOLED CHILLER SYSTEM with many

component chilling machines, AHUs, FCUs, Cooling

tower, Chilled Water Pumps, Condenser Water

Pumps, many types of valves, electrical & controls

etc.

Minimum parts thus very simple VRV

systems.

2 Energy Consumption Overall 25%-35% power saving on average basis. Only efficient at certain load conditions. Constant saving by optimal running.

3 Part Load operation Better Part Load efficiency Efficiency of system depends upon the following

parts.

Proportionate power consumption based

on load gives better part load efficiency

I. Chilling Machines Unit –Reciprocating, Screw,

Centrifugal Etc.

ii. Cooling tower

iii. AHUs, low side designing – Ducting etc.

iv. Operation of many pumps

4 Aircon BMS Controls Inbuilt feature full control options Specially implemented with Massive hardware

network for BMS operation

Extra & very significant cost in chilled

water systems.

5 Standby Function Inbuilt Standby – Multi-tier To be added at extra cost Ensured Operation all Times

6 Flexibility Complete flexibility for design, planning Limited Meets User Requirements

a) Installation & Commissioning Phase wise, floor wise possible. Not possible till full plant room operative

b) Operation 5 to 100% capacity control possible 20 to 100% capacity control possible

c) Heating option Inbuilt Feature Additional network to be laid Cost of the System Increase.

7 Interiors, Ceiling height Different Indoor Types options to fit into different

construction, interiors just 350 mm required within beams to

fit cassette units and ductable units

Only Ducted Systems possible, average 500 mm

drop below beams for installing AHU’s and Ducting.

Ceiling Level drops.

8 System Responsibility Single point responsibility of the total system installed Different manufacturers for different equipments Ensured Quality & Service Supports.

like chillers, AHUs, pumps, controls etc.

9 Distribution Piping Network Smaller copper piping in size. Bigger MS piping in size Bigger Shaft/ floor space required.

10 Electrical Panels Inbuilt electrical panel only additional isolators required to

control the Machine.

Individual power supply for all drives at multiple

location and separates operational equipment

required

Electrical cost to be more

11 Other Items

a) Water Quality Not Applicable Must for Make up to condenser water Circuit Daily Water Requirement

b) Water Storage Tanks Not required Required for continuous supply Bigger overhead, underground

c) Cooling Tower Not required Certain Size with Load bearing ceiling design Additional Major

d) Multiple Pumps Systems Not required Required in Chilling water systems Shaft/ floor space required

e) Heavy Foundations for

machines

Not required Required for Chillers, pumps, cooling towers, AHUs

f) Plant Room & Air Handling

Rooms

Not required Space for M/c room will be required Saving in lacs floor+ civil costs

12 Operations Friendly No Trained Manpower Required. Trained Manpower required User Friendly, operator cost

13 Installation Times Lesser Longer time periods for large low side works Lesser times for lesser low side works

14 Noise Very Less Extra precautions for plant room, AHUs room noise Installations time more

15 Service Benefits Self Diagnostic Features Not available beyond chillers for these complicated Faster service response

Electronic Controls systems of many components lesser break down, lesser down time

Service history, other functions help in services

Lesser service attentions Frequent servicing required

COMPARISON OF VRV SYSTEM Vs WATER COOLED CHILLED WATER SYSTEMS

S.No. FEATURE VRV SYSTEMS WATER COOLED CHILLER

SYSTEMS

Benefits

1 Fresh Air Plan In the Air-cooled VRV System fresh

air to be control 15-20% of the Indoor

Machine Capacity without changing

the configuration of the machine.

In the Water cooled system fresh air to

be control 10-100% of the Indoor

AHU/TFA.

Only Fresh air operated in

operations.

2 HRV Recirculation of the air only 15-20%

of the installed units.

Recirculation of the air only 10-100% of

the installed units.

Small Capacity Installed.

Why WATER ?

Conceptually.

R 20-30 Insulation

Triple glazing

No Thermal Bridging

Complete Airtightness

ACH 0.6

Geothermal Generation

Solar thermal Generation

ConventionalGeneration

Radiant UF

TABS

FCUs

MVHR

Heat Gain / loss

Thermal Mass

Air

Water

BEFORE GENERATION DISTRIBUTION MEDIUM

Savings Potential.

• Insulation R 30 can downsize the primary energy by 50-60%.

• Geothermal + TABS can reduce the primary energy by 60-70% over any forced air systems.

• Radiant Cooling can bring down primary energy by 40-50% over any forced air systems.

• Hence the Transformer / DG / back up / power cables all comes down.

R 30 insulation and Radiant cooling can bring down by 50%