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Nearly Zero Energy Buildings: A sneak preview of what technologies will make the cut

With Nearly Zero Energy Building (NZEB) regulations set to take the residential new-build market by storm in 2021, the burning question on many firms’ lips is what technologies are likely to be eligible under NZEB policy in the various EU heating markets? In our recent webinar we at Delta Energy & Environment explored the NZEB landscape in Denmark and Germany. Using our custom in-house NZEB model, we provided a sneak preview of our analysis into what technologies will make the cut, focusing on heat pumps and micro-CHP.

In this blog we’ll take a quick look at how the NZEB stacks-up in the heating market with one the most clearly defined set of NZEB regulations, Denmark.

A well-defined NZEB playing field: Denmark

The Danish NZEB building regulations (BR2020) in many ways set the bar for other member states as to what can be achieved on the back of the Energy Performance in Buildings Directive (EPBD). Under BR2020, new build residential dwellings will be required to meet the following requirements come 2021:

  • Maximum primary energy consumption: 20 kWh/m2/a
  • Maximum energy demand: 0.15 W/(m2.K)
  • Maximum indoor temperature: T > 26°C ≤ 100 hrs/a;  T > 27°C ≤ 25 hrs/a

Looking at the case for micro-CHP in Denmark, both internal combustion engine (1 kWe, 2.5 kWth) and fuel cell (0.7 kWe, 0.7 kWth) technologies were analysed in our model. For a nominal Danish new build dwelling with floor area of 140m2, eligibility was, perhaps unsurprisingly, found to be very dependent on the average heat transmission losses of the building.

Heat losses of 0.18 W/(m2.K), based on minimum insulation standards, led to a heat load of 12.5 W/m2, resulting in the following micro-CHP performance:

  • Engine-based micro-CHP failed to meet the NZEB requirements; 57.8 kWhPE/m2/a
  • Fuel cell micro-CHP met NZEB requirements; 13.9 kWhPE/m2/a

For the same building, reduced heat losses at 0.15 W/(m2.K) led to a heat load of 10.9 W/m2, resulting in the following micro-CHP performance:

  • Engine-based micro-CHP met NZEB requirements; 16.6 kWhPE/m2/a
  • Fuel cell micro-CHP met NZEB requirements; 7.6 kWhPE/m2/a

However, under these conditions the running hours of both systems was too low to make them a viable technology option.

Interestingly, under the same scenarios, a nominal air-source heat pump (3.3 kW) was found to fail to meet the NZEB requirements in both scenarios unless mechanical ventilation heat recovery (MVHR) was installed alongside it.

So what does it all mean?

With five years to go, the regulatory landscape around NZEBs remains diffuse in many European countries, although gaps are starting to be filled. Taking Denmark as an exemplar of the potential future impact of NZEB, it can be seen that heating technology eligibility really is still “up in the air”, even in markets with seemingly stringent regulations.

Beyond the sneak-peak preview provided above, we have investigated 4 other EU heating markets as part of our NZEB study, and got to the bottom of what heating technologies can make it big in this brave new soon-to-be NZEB-driven building world.

So what do you think of these initial findings? Who do you think will be the winners and losers of the NZEB revolution? Let me know at Alternatively, stay-tuned for our NZEB report, coming soon.



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Sunday, 18 April 2021

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