Bulgarian Energy Efficiency Consultant Exam flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

ZEE

Bulgarian Energy Efficiency Act; transposes EU Energy Efficiency Directive 2012/27/EU, mandates energy audits for large enterprises every four years.

ZEEU

Bulgarian Energy Performance of Buildings Act; implements EPBD 2010/31/EU, requires energy performance certificates for new buildings, sale, and rent.

SEDA

Sustainable Energy Development Agency; Bulgarian authority responsible for registering energy auditors and overseeing energy efficiency certification and audits.

NZEB renewable share

Bulgaria requires at least 55% renewable energy share for public NZEBs and typically 35% for other new buildings, per national regulation.

EN 16247-1

European standard for energy audits; specifies scope, data collection, analysis, reporting, and quality assurance requirements for a systematic audit.

Degree-day method

Heating degree days (HDD) equal the sum of daily differences between a base temperature and mean outdoor temperature when mean is below base; used to estimate heating energy.

Energy performance indicator

EnPI is a metric such as kWh/m²·year or kWh/unit production used to normalize and compare energy performance across buildings or processes.

Audit levels

Three typical energy audit levels: walk-through screening, detailed audit with measurements and energy balance, and investment-grade audit with financial analysis.

Thermal transmittance U

U-value is the rate of heat transfer through a building element per unit area and temperature difference, equal to 1/R_total, in W/m²K.

Thermal bridging

Localized areas of increased heat flow at junctions; quantified by linear thermal transmittance Ψ (W/mK) and included in envelope heat loss calculations.

Air permeability n50

Air changes per hour at 50 Pa pressure difference, measured by blower door test; NZEB target typically ≤3 h⁻¹ for airtightness.

Envelope heat loss formula

Q = U × A × ΔT (W), where U is thermal transmittance, A is area, and ΔT is indoor-outdoor temperature difference; annual energy uses degree days.

Heat pump COP

Coefficient of performance equals useful heat output divided by electrical input; seasonal SCOP accounts for varying outdoor temperatures and part-load operation.

Ventilation heat recovery efficiency

Ratio of temperature rise of supply air to indoor-outdoor temperature difference; typical 70–85% for balanced mechanical ventilation with heat recovery.

Lighting power density

LPD is installed lighting power per floor area (W/m²); typical limits are 10 W/m² for offices and 12 W/m² for retail spaces.

Boiler seasonal efficiency

Useful heat output divided by fuel energy input over a season; condensing boilers can exceed 90% based on lower heating value.

EPC energy class

Bulgarian scale from A+ (≤15 kWh/m²·year primary energy) to G (>250); based on calculated energy use for standard occupancy.

EPC validity

Energy performance certificate is valid for 10 years and required for new buildings, sale, rent, and public buildings over 250 m².

BREEAM

Building Research Establishment Environmental Assessment Method; international certification assessing energy, water, materials, indoor environment, and innovation.

NZEB definition

Nearly zero-energy building has very high energy performance with a significant share of renewable energy, typically at least 55% in Bulgaria for public buildings.

Simple payback

Investment cost divided by annual energy cost savings, expressed in years; a quick screening metric that ignores time value of money.

Net present value

NPV sums discounted annual cash flows minus initial investment; a positive NPV indicates the measure is economically acceptable at the chosen discount rate.

Internal rate of return

IRR is the discount rate that makes NPV equal to zero; a measure is acceptable if IRR exceeds the required rate of return.

Levelized cost of energy

LCOE equals total lifecycle cost divided by total energy produced over the system lifetime; used to compare different energy supply options.

Solar PV specific yield

Annual electricity output per installed kilowatt-peak; in Bulgaria typically 1,200–1,400 kWh/kWp·year depending on location and system design.

Solar thermal collector efficiency

Ratio of useful heat collected to incident solar radiation; flat-plate collectors typically achieve 40–60% efficiency.

Heat pump renewable share

A heat pump qualifies as renewable if its seasonal performance factor (SPF) is at least 2.5, per the Renewable Energy Sources Directive.

Battery round-trip efficiency

Ratio of energy discharged to energy charged, typically 85–95% for lithium-ion batteries; affects self-consumption and storage economics.

IPMVP Option C

Whole-facility measurement and verification method using utility meter data for the entire building, with adjustments for weather and occupancy changes.

Baseline period

Reference period of at least 12 months used to establish pre-retrofit energy use; adjusted for weather, occupancy, and production changes.

Weather normalization

Adjusting energy use to a common climate basis using heating/cooling degree days or regression with outdoor temperature, enabling fair comparison.

M&V savings equation

Savings equal adjusted baseline energy minus reporting-period energy, with adjustments for changes in occupancy, production, or building use.