Audits and inspections in HVAC

Auditorias e inspecções aos sistemas de

AVAC

Porto , 17th February 2010

J. L. Alexandre – DEMec/FEUP

DemSSo - Segurança e Saúde Ocupacionais

FEUP – Faculdade de Engenharia da Universidade do Porto

Fonte: IPCC, 2007: 4th Assessment report - Summary for Policymakers.

Climatic changes

Europe per capita CO2 emissions in 2006

Reductions needed in Europe could be ~ 80% [Average during

century] - Energy efficiency and reduction of energy consumption

Some Numbers Energy Use by Sector

1999

32%

38%

13%

9%

8%indústria

transportes

doméstico

serviços

outros

Transportes

35%

Serviços

13%

Agricultura

2%

Residencial

17%

Industria

33%

2005

Portugal

Europe

5

The air conditioned surface in Europe:

estimation of the stock to 2020 from EECCACCOOLED AREA IN Mm2

0

500

1000

1500

2000

2500,

3000,

Stock 1990 Stock 1995 Stock 2000 Stock 2005 Stock 2010 Stock 2015 Stock 2020

RAC

RooftopsPACK & Large Split

VRF

Chillers

COOLED AREA IN Mm2

0

500

1000

1500

2000

2500,

3000,

Stock 1990 Stock 1995 Stock 2000 Stock 2005 Stock 2010 Stock 2015 Stock 2020

COOLED AREA IN Mm2

0

500

1000

1500

2000

2500,

3000,

Stock 1990 Stock 1995 Stock 2000 Stock 2005 Stock 2010 Stock 2015 Stock 2020

RAC

RooftopsPACK & Large Split

VRF

Chillers

RAC

RooftopsPACK & Large Split

VRF

Chillers

6

Introduction

• In Europe more than 40% total energy is used in building

sector .The sector is expanding, which is bound to

increase its energy consumption .

• New challenger demands reduction up to 20% in the next

20 years (3 x 20). In 2020, 20% energy reduction and

less 20% of gas emissions)

• Europe adopted new directives to implement the

reduction target in building sectors (tertiary and

residential sector) – EPBD [ Energy performance in Building Directive]

– Directive 2002/91/EC and

– the new recast – Directive 2010/31/EU

• Inspections and Audits of HVAC is part of the solution –

Energy management

Energy Audit Types according the HarmonAC

AUDITAC EP

• Pre-inspection

– Walk - through audit

– Analysis of utility bills

• Inspection

– Standard audit

• Audit

– detailed Audit - mainly in the AC system

Pre-inspection

Visit the facility to determine the important systems that use energy sources.

Identify and assess maintenance and operation strategies that do not require high investment.

Pre-inspection

(Analysis of Utility Bills)

Collect all utility bills (electricity, fuel, water, steam,

etc.)

Analyze the variations of the utility bills over several

years or periods

Identify other favorable utility rate structures available

for the facility

Verify if the utility costs are calculated correctly

10

Checklist of pre-inspection information for AC system

Inspection - General Procedure

Collect all relevant data related to the facility

(construction details, retrofits, etc.)

Visit the facility

Develop a base-case for the facility

Identify and evaluate measures to save energy

cost and/or improve comfort

Classify the measures using an economic

analysis

Inspection methodology: general

AC Equipments

The introduction of the standard contains:

Instructions for measurements method, calibrated

measurement instruments

SIZE NEEDS

Compare the installed cooling capacity

to the estimated cooling needs

Estimate Specific Fan Power (standards

EN 12599 and EN 13779)

Inspection Methodology

• Inspect refrigeration equipment• Inspect for effectiveness of outdoor heat rejection• Inspect for effectiveness of heat exchange to the

refrigeration system (indoor units of split and distributed systems)

• Inspect cooled air, and independent ventilation air, delivery systems in treated spaces

• Inspect cooled air, and independent ventilation air, delivery systems at air handling units and associated ductwork

• Inspect cooled air, and independent ventilation air, delivery systems at outdoor air inlets

• Inspect building system controls and control parameters

• Energy consumption metering• Reporting

Advice on alternative solutions and improvements

Significant opportunities to reduce cooling loads (low cost improvements )

Improvements/renovation

Or replacement!

:

Cooling load reduction

Alternative cooling

techniques

IR Thermography - Boiler

IR Thermography: Chiller condenser / evaporator

Assessing the chiller / heat pump performance with

Climacheck

CLIMACHECK

Refrigerant fluid temperature at different points of the chiller / heat pump

0

10

20

30

40

50

6015:04:50

15:06:40

15:08:30

15:10:20

15:12:10

15:14:00

15:15:50

15:17:40

15:19:30

15:21:20

15:23:10

15:25:00

15:26:50

15:28:40

15:30:30

15:32:20

15:34:10

15:36:00

15:37:50

15:39:40

15:41:30

15:43:20

15:45:10

15:47:00

15:48:50

15:50:40

15:52:30

15:54:20

15:56:10

15:58:00

15:59:50

°C

Comp1_OUT

Comp1_IN

Cond1_OUT

Comp2_IN

Comp2_OUT

Cond_W_IN

Cond_W_OUT

Cond2_OUT

19Easy to implement actions, no need

for detailed audit, Operational

Checking the

envelope use and

structure

Visual inspect the

plant

Check for the

presence of O&M

activities and

contract

Activating the

detailed audit tasks

Considering a list of

energy conservation

opportunities (ECOs)

Actions taking

place during

preliminary audit

Reduce internal loads

Improve insulation

Add solar shading

Install BEMS

Change the setpoint

temperatures

Calculate the savings from

load reduction through

replacement with

EnergyStar facilities

Use better filters

Optimise the filter

replacement frequency

Feasibility,

need for

details

Yes No

Yes No

Yes No

Yes No

Yes No

Yes No

Yes No

Assess the investment

for envelope changes

Calculate the

investment

Asses the impact on

solar loads reduction

Calculate the best

investment with savings

©JLA - FEUP

General Procedure

(Detailed Audit)

Perform the same tasks outlined for the

standard audit

Establish a base-case for the facility thermal

systems using a simulation program (DOE-2,

TRNSYS, Energy +, Energy 10, ESP-r, etc)

Monitor energy consumption by end-uses of

the facility (lighting, plug-load, cooling plant,

etc.)

IAQ requirements

energy breakdown to know where we can

actuate to reduce the energy consumptions

Inspection an Audits

• What is the best way to produce energy audits and inspection

efficiently and quickly, of course and safety?

• Many methodologies are based on CEN Standard EN 15240 and

CIBSE TM44 – we need harmonization to produce standards

• Methodology based on Field Trials and real case studies Case

Studies

Results

• Some substantial savings (up to 60%) appear available to be identified by

inspection.

• An Inspection of an A/C system would appear to take between 5 hours to

over 2.5 days on average.

Working in Progress:

- Energy survey in real cases

- Indirect methods for chillers energy efficiency analysis

Final Results of European Project

• Last 3 years 400 HVAC inspections and audits was made

around the Europe and the results were:

• The total of energy savings for all inspections and audits

was 37.9 to 112.2kWh/m2

• i.e ± 16.2Mtoe (±11% of total energy used in tertiary

building sector), which is equivalent to avoid the

emission of 62.9Mt of CO2 emissions per year. 22