Passive Housing and the concept of the Passive Solar House have been around for many years. In Ireland we have many examples of what was known as the Passive Solar House. It was quite different to the PassivHaus concept developed and made successful by Wolfgang Feist and the Passiv Haus Institute in Germany.
The Passive Solar House in Ireland
The Passive Solar House, particularly in Ireland, did not feature the very low U-Values as are now prevalent in Low Energy Housing. This was probably for four reasons:
Firstly, we had not developed the methods of building which were readily and economically available to achieve very low U-Values in practice. Some wall constructions were designed to give low U-Values but in reality did not do so in practice due to site construction problems. Similarly triple glazed windows were not economically available through Irish suppliers.
Secondly, it was found difficult to build houses to levels of airtightness that were deemed necessary for low energy housing
Thirdly, eliminating Thermal Bridging was difficult given the methods of construction and the methods of analysis available at the time
Fourthly, the Irish construction industry simply was not ready to be forced into the highly specialised techniques to achieve the U-Values and airtughtness required and also and probably most importantly, there simply was not the will to deliver a near 'zero-energy' house.
This gave rise to an extraordinary situation where the 'Low Energy House' in practice could cost considerably more to run than the actual design amount as is illustrated in the bar chart (Fig 1) below. If the actual heat losses are doubled – which could well be the case because of poorly installed insulation, lack of airtightness and serious thermal bridging – then the running costs tripled over the design value as the amount of solar gain remained approximately the same.
With this knowledge and with the growing number of Architects and Engineers interested in this area of Low Energy House technology a number of examples were built.
Probably the first serious example of a Passive Solar House in Ireland was the Garristown House in Co Dublin – built between 1979-'80. The concept design was by the well known Engineer and specialist in Thermodynamics John Cash for whom the house was actually being built. Duncan Stewart was the Architect and other colleagues of John and Duncan in DIT were also involved in various aspects of the house design. Huge efforts were made to ensure that this house achieved its design values and indeed it was such a success that it sparked considerable interest in this area. As can be seen from the photo this reasonably well insulated house featured a massive Solar Wall of some 110 m2.
Photo 1: The Garristown Passive Solar House
Another example of a Passive Solar House built a little later than the Garristown House was the Knocklyon Solar House – built and monitored between 1983 and 1989. This house featured an early version of a Solar Heating and Ventilation system eventually evolving into NuTech's Sunwarm system, this early system had 40m2 (gross) of air solar collectors. In reality this was a Passive Solar House with and Active Solar feature. The collector array fed energy into the heating and ventilating system and into the domestic hot water system. The wall insulation in this house – an early version of bonded bead - proved troublesome and had to be replaced by blown fibreglass. Difficulties were also experienced in attaining a high degree of airtightness. Many different systems were tried and tested in this house including air solar collectors, Phase Change Material Heat Storage, Solar Assisted Heat Pump technology, to name a few. A huge amount of information was gathered by way of the data monitoring system, the results of which were reported to the Energy Directorate of the European Commission.
Photo 2: The Knocklyon Passive Solar House
The Knocklyon project in particular led the way to a simplified Passive Solar House concept developed by both Mark Forkin and Bill Quigley of NuTech. This concept can achieve the same results as a more expensive to build Passive House. Details of this system together with a comparison can be found here.