FEUP Faculdade de Engenharia da Universidade do Porto Audits and inspections in HVAC Auditorias e inspecções aos sistemas de AVAC Porto, 24th September 2010 J. L. Alexandre DEMec/FEUP
Climatic changes Fonte: IPCC, 2007: 4th Assessment report - Summary for Policymakers.
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 Portugal 1999 Serviços 13% Agricultura 2% 8% 9% 13% 32% indústria transportes doméstico Residencial 17% Transportes 35% 38% serviços outros Industria 33% 2005
The air conditioned surface in Europe: estimation of the stock to 2020 from EECCAC COOLED AREA IN Mm2 3000, 2500, 2000 1500 RAC Rooftops PACK & Large Split VRF Chillers 1000 500 0 Stock 1990 Stock 1995 Stock 2000 Stock 2005 Stock 2010 Stock 2015 Stock 2020 5
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 6
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.
JLA - FEUP 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
Checklist of pre-inspection information for AC system 10
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
15:04:50 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 CLIMACHECK Refrigerant fluid temperature at different points of the chiller / heat pump 60 50 40 30 20 Comp1_OUT Comp1_IN Cond1_OUT Comp2_IN Comp2_OUT Cond_W_IN Cond_W_OUT Cond2_OUT 10 0
JLA - FEUP Easy to implement actions, 19no need for detailed audit, Operational Actions taking place during preliminary audit Checking the envelope use and structure Considering a list of energy conservation opportunities (ECOs) Reduce internal loads Improve insulation Feasibility, need for details Yes Yes No No Activating the detailed audit tasks Calculate the savings from load reduction through replacement with EnergyStar facilities Assess the investment for envelope changes Add solar shading Yes No Asses the impact on solar loads reduction Visual inspect the plant Install BEMS Change the setpoint temperatures Yes Yes No No Calculate the investment Check for the presence of O&M activities and contract Use better filters Optimise the filter replacement frequency Yes Yes No No Calculate the best investment with savings
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 efiency analisis