Posted: November 19th, 2022

Passive and HVAC design of Azuma House by Tadao Ando

Engineering and Construction
Topic:
Passive and HVAC design of Azuma House by Tadao Ando
Describe the existing heating and cooling systems of the building. Note whether it is exclusively hydronic, air, or a combination. Describe the passive design strategies.
Introduction
The Azuma House model is presented in Figure 1 below. The Azuma House was designed by Tadao Ando in 1976; the house is divided into three section; two enclosed interiors, and courtyard, which is centrally situated. And at the first flow the courtyard is crossed by a bridge. The paper explores how the heating and cooling are achieved, and also the passive strategies employed in the realization of the same.

Figure 1: Model of Azuma House
Heating and cooling system
The Azuma house is made in such a way the glass walls face inside, minimal wood furnishing, and the material used most is the cast concrete. The specific heat capacity of cast concrete is high which enables it to absorb much heat. The materials of the house and the presence of courtyard contribute to the heating and cooling system of the house.
Courtyard: This part is exposed to the natural weather outside the building. The concrete gets heat energy from the sun through radiation. The heat received cannot be realized easily; so it is stored throughout the day. There is thus a gradual rise in temperature due to continuous absorption of heat during the day. The ground hence has the ability to retain heat for a long time during the day, particularly in summer seasons. But because of the rise of the hot air molecules rise, the temperature of the occupancy area can get overheated and become uncomfortable. The large surface area to volume ratio resulting from placement of courtyard in the middle offers a great provision for heat loss.
Interior: every room has four surface areas of exposed concrete which conduct heat; however, the floor made of the wood for insulation purposes. There is possibility of the contact between the occupant and the enveloped building being that the scale of the building is small; thus making it comfortable during the summer and uncomfortable during winter. The ceiling is made of glass pane. The substantial temperature difference across the ceiling will initiate convection current which circulates warm air into the cooler courtyard. Therefore, the temperature of the room fluctuates and become unpredictable. Furthermore, being that there are no apertures for penetration, the radiation waves reflected off are absorbed inside thus making the room warm, but this is also useful only during winter.
Passive Design strategies
The two passive design strategies in Azuma House are stack effect and high mass cooling.
Stack Effect: wind traveling at high speed directed over the Azuma House establishes a region of low temperature hence drawing warm air from the courtyard. If the air in the courtyard gains heat as a result of thermal radiation, its buoyancy reduces, leading to the rising of air. And this leads to the realization of the convection of cool air from the inside to the outside via the glass pane. The rise in warm air molecules leaves behind an area of low pressure which then draws the cool air (at high pressure) to fill the void.
High Mass Cooling: The concrete materials which form the major part of the Azuma House has high heat capacity which enable them to hold the accumulated in the daytime, and to release the heat slowly to the surroundings at night time. The thermal mass cooling is helpful in ensuring that there is no sudden change of temperature from warm to cool.

Bibliography
Davies, Colin. Key houses of the twentieth century: plans, sections and elevations. London, UK: Laurence King Publishing, 2006.
Habraken, N. John, Andrés Mignucci, and Jonathan Teicher. Conversations with form: a workbook for students of architecture. Abingdon-on-Thames, England: Routledge, 2014.
Odgers, Jo, Flora Samuel, and Adam Sharr, eds. Primitive: Original matters in architecture. Abingdon-on-Thames, England: Routledge, 2006.

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