june 2003 dr christine pout calculations - breprojects.bre.co.uk/epbd/pdf/christinepout.pdfdr...
TRANSCRIPT
Implementing Energy PerformanceCalculations
Dr Christine Pout
30th June 2003
Background
� FBE project last year exploring how simplified energysimulation tools could be used for the EPD
� Follow on research project which aims to develop a prototypedemonstration energy calculation tool –� Focus on the inputs and outputs
� Input data requirements/availability
� Uses of energy performance information
Overview
� Directive requirements and aims
� Defining energy performance
� Essential and desirable features of an energyperformance calculation methodology
� Information needed to determine energy performance
� The process of calculating energy performance
� Standardized occupancy, benchmarks and minimumstandards
� Provision of advice of EE improvements
Requirement and Aim of the Directive
� Requirement of the Directive – Measure the energyperformance, suggest improvements, extend minimumstandards to existing buildings.
� Aim of the Directive – Save Carbon
� Routes for meeting the aims of the Directive� Directing potential occupiers to choose/specify lower carbon buildings� Encouraging owners/managers to reduce a building’s carbon
emissions� Setting minimum standards to eliminate worst energy performers
� The Directive is an enabling step to achieve carbon saving
Defining Energy Performance
� The predicted energy performance
� For a standard level of service demand and occupancy– (theintrinsic energy performance)
� For a standard level of service demand and the actual occupancy
� For the actual level of service demand and the actual occupancy
� The actual energy performance
Presenting Energy Performance
� Energy Consumption (Delivered or Primary) and/orCO2 emissions
� per building / per unit floor area
� Normalised – for what?
� for external wall area/building shape
� region/external conditions
Essential/Desirable Features
� Minimize data input requirements/work with available data
� Consistency of results – repeatability
� Single procedure to cover� all relevant building types
� new and existing buildings
� Capable of showing compliance with minimum energystandards
� Provide a basis for energy efficiency advice
Factors Affecting Energy Performance
� Performance of the building envelope, e.g., thermalcharacteristics, Air infiltration rate
� Efficiency of heating, cooling, ventilation and lighting systems
� External conditions
� Service level requirements e.g., Internal temperature range,lighting levels and occupied hours
� Internal gains
� Building Operation Strategies
Energy Performance Calculation Process
Calculation Engine
Occupancy Details (temp, internal gains, hours)
Fabric Details
Regional Weather Data
System Performance
Energy Peformance Rating
Predicted EnergyConsumption
Data Required - energy performance
� New build - plans/design data� U-values of fabric elements, orientation etc.
� Heating, cooling, ventilation and lighting system types specified
� Installed capacity and efficiency of equipment
� Existing building - site survey� Observations of the building materials and envelope characteristics
� Visual assessment of (probable) system type
� Installed capacity and efficiency of equipment (where accessible)
� Log Book requirement (Part L2) useful source
Data Inputs for new buildings
yes
no
Calculation Engine
Standard Occupancy details (temp, internal gains, hours)
Fabric Details
Regional Weather Data
System Performance
Predicted EnergyConsumption
Modelled Building Service Details (HeatingCooling Lighting)incl. controls data
Typical System Performance
Data Inputs for Existing Buildings
yes
no
Calculation Engine
Standard Occupancy details (temp, internal gains, hours)
Fabric Details
Regional Weather Data
System Performance
Predicted EnergyConsumptionActual System
performance data available
Typical System Performance data
Building Type/Age plusSurvey
Construction data available
Infer
Standardized Occupancy Patterns
� Need standardized occupancy to allow fair comparisonbetween buildings
� Need to define a number of fixed building types (based onfunctionality) - Could be constructed using an activity basedapproach� e.g., Office = 75% office space, 15% circulation space 5% washrooms
5% storage.
� Buildings could be rated for more than one building usecategory.
Comparing Energy Performance
� Standardized energy performance provides the bestway for a buyer/tenant to compare the likely energyperformance in use between buildings
� Comparing calculated energy performance based onactual occupancy with actual energy consumption isbetter for determining operational energy savings
Calculating Consumption based on ActualOccupancy
Calculation Engine
Standard Occupancy Details (temp, internalgains, hours)
Fabric Details
Regional Weather Data
System Performance
Predicted EnergyConsumptionStandard Occ
Actual Occupancy details (temp, internal gains, hours)
Predicted EnergyConsumption(Actual Occ)
Actual Energy Consumption
OperationalSavings Potential
Benchmarks
� Empirical benchmark – based on the range of actualperformance for a building type.
� Tailored benchmark – adjust empirical benchmark to yourspecific building operation e.g., longer operation hours etc.
Comparing Actual Consumption
Comparing Actual energy consumption with
� Empirical benchmarks - tells you how well you aredoing compared to others in your “broad” class
� Tailored Benchmarks – (which can account forparticular mix of activities, occupancy patterns andfabric) tells you where your performance is comparedto where it should be.
Meeting minimum standards
� Could set minimum energy performance values for eachbuilding type
� Could compare energy performance rating to that of anexemplar building
� Could compare energy performance to one meeting minimumstandards e.g., elemental method Part L2.
Provision of advice of EE improvements
� Could be entirely separate from energy performancecalculation� Based on detailed energy audit and expert advice
� Generic (Action Energy Material)
� However, most energy advice requires much of the sameinformation as the calculation of energy performance. Socould add a decision tree onto energy performance calculationprocedure
Providing Energy Efficiency Advice
Calculation Engine
Occupancy details (temp, internal gains, hours)
Fabric Details
Regional Weather Data
System Performance
Predicted EnergyConsumption
Tailored advice plus info on typcial savings/cost effectiveness
Decsion Tree
Integrated Energy Saving Advice
� Rather than relying on typical savings, could use theprocedure to calculate the savings achievable in a particularbuilding.
� Calibrating the calculation to the actual energy consumptionwould� ensure more accurate assessment of the energy savings� Allow achievable operational savings (as well as fabric and system
savings) to be accurately assessed.
� Using this route also enables the cost effectiveness of energysaving measures to be assessed
Providing Energy Efficiency Advice and CostEffectiveness Calculator
Calculation Engine
Occupancy Details (temp, internal gains, hours)
Fabric Details
Regional Weather Data
System Performance
Calculation Engine
Occupancy Details (temp, internal gains, hours)
Fabric Details
Regional Weather Data
System Performance
Original EnergyConsumption
Energy Consumption with EE measure
ApplyEnergy Savings Options
Adjust Input Values
Carbon and Cost Saving
Cost of EE Options
Cost Effectiveness