2016-07-22|Sunatori's Optimisation (Indoor Temperature Control via Thermal Inertia)

Potential Discovery or Invention

• My house is equipped with a central heat pump system, but I did not used it at all for air conditioning in a year which had record high temperatures in Canada. In fact, the heat pump was completely OFF for 6 months from May to October.

• Here is my method to optimise indoor temperature without activating the air conditioning function of the heat pump. It takes advantage of thermal gradient (the fact that hot air goes up and cold air goes down), and of thermal inertia (the degree of slowness with which the temperature of a body approaches that of its surroundings) in a climate with relatively large temperature difference between day and night in a multi-stage building which has high thermal capacity.

• The lower/upper floor windows are on the opposite sides (north-south or east-west). For ventilation in summer, the air inlets on the basement were opened while those on the upper floor were closed. The indoor temperature is measured on the lower floor where most of my activities take place.

• The method can be reversed in spring and in autumn with different parameters to capture warm air from the outside during the day. Also, it is advised to keep a warm blanket throughout the year.

  time period	temperature outdoor	temperature indoor	window lower floor	window upper floor	ventilation
  00:00 - 04:00	15 C	20 C	open	open	on
  04:00 - 08:00	15 C	20 C	open	open	on
  08:00 - 11:00	20 C	20 C	open	open	on
  11:00 - 14:00	30 C	25 C	closed	open	on
  14:00 - 17:00	35 C	30 C	closed	closed	on
  17:00 - 20:00	30 C	25 C	closed	open	on
  20:00 - 00:00	25 C	25 C	open	open	on

• Here is pseudo-code of the switching algorithm without hysteresis.

  if (MM >= 05) or (MM <= 10) then   repeat     if (temperature[indoor] > 30) then       put "closed" into window[lower floor]       put "closed" into window[upper floor]       put "on"     into ventilation[central]     else if (temperature[outdoor] > temperature[indoor]) then       put "closed" into window[lower floor]       put "open"   into window[upper floor]       put "on"     into ventilation[central]     else       put "open"   into window[lower floor]       put "open"   into window[upper floor]       put "on"     into ventilation[central]     end if     wait 300 seconds   end repeat end if

Potential Discovery or Invention

• The hyper-automation algorithm was coded in Apple's Shortcuts app (iOS).

  

• Saying "Hey Siri, Windows" gathers data from the Weather app and from the Sensi app, and generates advice to "Close the windows!" or "Open the windows!", followed by opening the Weather app.

  

Potential Discovery or Invention

• My 30-year old air-to-air heat pump still functions OK even at -30 C, but I noticed that its RED indicator light turns ON and the outdoor unit stops running quite often in spring. I have finally figured out that it is because the coil's low temperature relative to the ambient temperature of just above the freezing point (0 C) of dihydrogen monoxide (H2O) causes condensation at the outdoor unit, and the resulting frost blocks the air flow at the coil, lowering the heat pump's efficiency below the threshold to trigger an Emergency situation.

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"Sunatori, Go Simon" <GS.Sunatori@HyperInfo.CA>

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• Produced in Canada./Produit au Canada.

ISBN 978-0-929105-04-8

• 2024-12-17T20:39:03.000Z