Hierarchical HVAC

Thinking of upgrading your HVAC system? Heating and cooling a Brooklyn brownstone is a multifaceted thing. There are many ways to do it. Is there one best way? Maybe…generally speaking….but I am not there yet with the definitive answer. Most brownstones have the same characteristics so I think there are probably universal applications….but I’m still exploring what they are.

But before you even start thinking about HVAC there are key things that need to be done to a house. They are related to the house Efficiency. They are:

a. passive solar (let the sunlight in or block it depending on your needs)
b. air sealing
c. insulation
d. operational efficiencies (heating where it needs it, not everywhere)
e. sweater application (or speedo application, depending on where you live and your heating/cooling needs)

The main point of the above list is that you want to increase the efficiency of a house before you start adding things like heating or cooling. Plugging holes, fixing leaks, putting on a blanket, and letting the sun in has priority over new HVAC equipment and upgrades.

Just about every structure leaks to some extent, some a great deal more than others. If the fuel tank in your vehicle had a leak, would you fix it or just stop by the fuel station more often? The same goes for a house. Fix the leaks then decide how much heating and cooling you need.

Here is a list I gleamed from one of my email lists. It breaks down HVAC into categories so as to visually see the options.
First you have the type of fuel you use (eg. natural gas).
Then how you produce the heat (eg. Boiler).
Then how you deliver that heat (eg. pumped water).
Then how you store the heat (eg. thermal mass).
Then how you disperse the heat (eg. water radiators).

There is overlap between these things. Some serve two purposes. And there is more to the list. But it is a beautiful list and a great starting point.

HVAC LIST:

1. Fuel
a. Solar
i. PV (Electricity)
ii. Thermal
A. Air/Air
B. Air/Water
C. Water (nominally — liquid)/air
D. Water/Water

b. Fossil Fuels
i. #2 Fuel Oil
ii. Propane
iii. Natural Gas

c. Biofuels
i. Wood
A. Cut/Split
B. Wood pellets
ii. Other Biofuels (biodiesel, corn: getting lazy)

2. Heat Production
a. Furnace (i.e. Hot air)
b. Boiler (i.e. Hot water)
c. Direct Combustion
d. Heat pump, Water/Water
e. Heat pump, Air/Air
f. Heat pump, Air/Water
g. Heat pump, Water/Air
h. Passive Solar

3. Heat Delivery
a. Convective water (or gravity-driven)
b. Pumped water
c. Convective air
d. Forced hot air

4. Thermal Storage or thermal RC modifiers
e. Phase change materials
f. Thermal mass
h. Thermal mass to water heat exchangers
i. Thermal mass to air heat exchangers

5. Heat Dispersal
a. Convective
i. Water radiators
ii. Water baseboards

c. Air registers
d. High speed air vents
e. low temp radiative surfaces
f. high temp radiative surfaces

About the author: Gennaro Brooks-Church

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  1. Michele - September 21, 2009 at 3:42 pm

    I love geothermal for heat and air but you are absolutely right about making sure your home is efficient! It does no good to have a great system if there are cracks in the windows or doors! Thanks for the tips.

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