IR pictures Hoe goed is jouw woning?

How to assess the energetic quality of a dwelling? To know = to measure But: “De spreiding in het gasverbruik van woningen in hetzelfde project bleek door het gedrag van de bewoners zo groot dat er geen statistisch significante relaties konden worden vastgesteld tussen energieprestatie en gasverbruik.” RIGO, Energiegedrag in de woning; aanknopingspunten voor de vermindering van het energiegebruik in de woningvoorraad, RIGO i.o.v. VROM/WWI, 2009.

I Objective & approach

Determine the ‘energetic’ quality of a dwelling and assess the effect on user behaviour on the result(s). ‘energetic’ quality of a dwelling → heat losses [W/K] 3 different sets of data yield three values : 1.theoretical or expected heat losses, 2.overall heat losses from the energy balance in the heating season 3.measured heat losses, using the ‘energy signature’ method 4.heat losses from InfraRed pictures

Three types of heat losses 1.Theoretical or expected heat losses What one might expect based U-values, ventilation rate, air tightness etc. 2.Overall heat losses from the energy balance in the heating season Measured value, but affected by e.g. indoor temperature, mildness winter 3.Measured heat losses, using the ‘energy signature’ method Measured value, does not depend on e.g. indoor temperature, internal gains etc.

1. Theoretical or expected heat losses

2. From energy balance (heating season) heat losses = sum gains / (T in -T amb ) av

3. Heat losses from the ‘energy signature’ user behaviour (indoor temperature, internal heat gains) only shifts the line, does not affect the slope independent of the climate (see graph ) energy demand for DHW from summer consumption Heat losses = slope of trend line Plot of energy consumption in a period vs.average ambient temperature

Correction for solar gains Consumption corrected for solar gains from no. of sunshine hours in each period solar gains cause scatter in spring, autumn

E-signatures: shot of hail?

Uncertainty in the results 1.Theoretical or expected heat losses record variation from plausible range of input parameters % uncertainty =  [(5%) 2 + (10%) 2 + (12%) 2 + ….] 2.Energy balance heat losses record variation from plausible range of input parameters % uncertainty =  [(5%) 2 + (10%) 2 + (12%) 2 + ….] 3.Energy signature heat losses

Results comparable  energetic quality as expected and comparable results 1-3 W/m 2 K ~ kWh/m 2 a = int gains + solar + heating

Nul-energie-tool: warmtevraag rvw

Nul-energie-tool: warmtevraag ov. maatregelen

Nul-energie-tool: inzet opwekker rendementen

Conclusies Simpele methodologie voor het bepalen van 3 typen warmteverliezen geeft vergelijkbare resultaten  valide aanpak Alle 3 methoden lijden aan de moeilijkheid van verkrijgen van nauwkeurige input data, maar onder die omstandigheden leveren gesofistikeerde modellen geen beter resultaat Nul-energie-tool is een herschikking van onderdelen van de warmteverliesberekeningen Validatie van de Nul-energie-tool in voorbeeldwoningen lijkt een goede volgende stap