Net Zero buildings 1

[cry22]

High all,

I could not afford to go to the ASHRAE show on net zero in san Francisco this past month.

Can anyone volunteer information on the show if possible?

How do we HVAC engineers contribute to net zero buildings? We can reduce energy, but what are the big features of a net zero building besides installing a geothermal/wind turbines/solar panels and the likes.

What is the definition of Net zero as used today? 100% on-site waste treatment? energy producing facility?

Similarly, what is the definition of a carbon free facility as used today?

Thank you

 

[GMcD]

Envelope, envelope, envelope. The Building Systems engineer contributes by helping the Architect design the best possible envelope in terms of insulation, fenestration optimized for daylighting, with exterior shading optimized for elimination of solar heat gain, and reduce the building loads as far as possible BEFORE applying building systems and techno-solutions. Google things like Passivhaus, Minergie, Low Exergy, and do some self-learning on how to achieve these aspects. Look at building heating and cooling systems that are low intensity hydronic radiant based with some kind of minimum heat/energy recovery ventilation dedicated outdoor air systems (DOAS).

The definition of "net zero" is still under discussion - does it mean net zero based on a yearly average use (use some energy from the grid, but put back more than you've used over the year), or use zero energy from the grid period? Or use net zero of all kinds of energy in a Living Building scenario? (See Cascadia Living Building Challenge)

Carbon neutral- same thing- means different things to different people, there's still a variety of carbon neutral definitions.

 

[giap1]

Net Zero buildings are the ones that produce all the energy they consume.No possible in the U.S. (due the wheather challenges)but as GMcd said the envelope characteristics help a lot.

 

[RossABQ]

More to the point, are there any developers/owners who are willing to pay up-front costs and maintenance for this complex a building over its lifetime, even past the time that election rhetoric has faded?

 

[GMcD]

RossABQ: Not sure where the assumption is that a net zero or low energy building is "complicated". Whats complicated about high performance windows, openable windows, passive natural ventilation and cooling, building thermal mass utilization, well designed air tight structures, and simple heat/energy recovery ventilators, with maybe a few solar water heating panels. Granted there ARE climate zones in North America that would take a bit of extra effort to resolve hot'n'humid climate issues, but fundamentally a low energy/high perfomance building relies primarily on passive envelope features that require little to no maintenance compared to "active" building systems.

Electrical energy would be the primary energy need for the building which can be generated on site by any number of mainstream renewable generation sources, PV panels, Wind generators, combined heat'n'power, etc. No more maintenance intensive than a boiler/chiller plant, or packaged rooftop DX cooling systems.

 

[RossABQ]

GMcD, no disagreement about the value of passive features and construction features. Also no question to achieve net-zero there is significant added capital cost in those areas.

As for PV, wind energy, and combined heat'n'power et al being "mainstream", I think that's a stretch in the context of commercial (for-profit) buildings. But I see your point, if you are able to completely eliminate a bunch of mechanical equipment, the maintenance costs could become similar. Whether these systems prove to be as durable as familiar traditional systems is a key point in their life cycle costs.

 

[ChrisConley]

My personal thoughts are that most of the 'over the top' net zero strategies are for marketing and green washing only.

All buildings need electricity. Reduction of peak electrical loads through envelope, lighting design, fenestration, variable motor technology,cooling strategy and a variety of other 'proven' technologies are the best ways to impact the 'footprint' of a building.

Using PV, wind farms and CHP to 'take the building off grid' are pure and simple a waste of money. Money that would be better off invested in central power plants, where the effect is felt by everyone on the grid. If you have the money to spend donate it to your local power utility requesting that they spend it on green power development.

 

[cry22]

check this out

http://www.masdar.ae/en/home/index.aspx

 

[RossABQ]

Interestingly, even the Sheiks have decided money is tight for such an adventure, and have recently sent home many of the consultants and contractors. It will be worth watching to see if they pursue it as the price of oil fluctuates.