Introduction

Although the Channel Islands has de-carbonised its electrical power supply systems, it has not managed to transition to low carbon heating for all its housing stock.

In the Channel Islands many properties are still heated with oil. Retrofitting our private sector higgledy-piggledy homes is so expensive that it will take a lot of effort and design changes to decarbonise. Also our old Victorian hospital in Jersey and many other Channel Island public buildings fall into this category.

If the Channel Islands are to meet their commitments to address climate change then we must make all our buildings low carbon and energy efficient.

The Channel Islands should play its part by retrofitting its old buildings to become much more energy efficient and, in future, construct highly energy efficient new builds.

However, this is easier said than done! The Passivhaus certification process could help the Channel Islands meet the highest possible standards.

Therefore, it would also be highly appropriate if Jersey could take its cue from this event by ensuring that its future hospital is energetically the most efficient in the British Isles.

Brief Overview of what is entailed constructing a Passivhaus Hospital

Due to their intensive 24-hour use, hospitals consume large amounts of energy. From the accident and emergency department and operating theatre to patient rooms, numerous technical devices are in continuous use and the lights are on practically all the time.

 

Hospitals have got to be designed with energy efficiency in mind. This is where the new hospital built in Frankfurt comes into its own. This hospital was constructed to full Passivhaus standards.

The core focus of Passivhaus is to dramatically reduce the requirement for space heating and cooling, whilst also creating excellent indoor comfort levels. In a Passivhaus building, thermal comfort is achieved through use of passive measures. These measures can be applied not only to buildings in the residential sector but also to commercial, industrial and public buildings.

Such buildings are called "passive houses" because a major part of their heating demand is met through "passive" sources such as solar radiation and the waste heat from occupants and technical appliances. A Passivhaus building thus consumes about 90 percent less heating energy than existing conventional buildings and 75 percent less energy than an average new construction.

In all modern hospitals it is desirable that the temperature of patient rooms and wards should remain at 22 degrees Celsius.

The Passivhaus design can meet its lower energy requirements because it incorporates triple-glazed windows, higher levels of thermal insulation, and recycles waste heat.

Generally speaking, the electricity consumption in a conventional hospital is three to four times higher than that of a residential building. Hence it is vital that every part of a hospital design should be well thought about.

It is clear that hospital equipment has a major influence on energy demand and that this must be taken into account when designing a new hospital e.g. the computers and magnetic resonance imaging devices alone account for eight and seven percent respectively of the energy demand, whilst the energy required in sterilising medical equipment accounts for a good four percent.

Conventional hospitals studies have shown that these are normally equipped with more devices than necessary and that these devices often also have not been optimised for energy efficiency.

Hence, a Passivhaus Hospital, by design, uses only the most energy efficient devices. This will also reduce the need for cooling.

Every Passivhaus building is equipped with a ventilation system that has a heat recovery mechanism that ensures that fresh preheated air constantly flows into the rooms.

Of course, it will still be possible to open the windows in the Passive House hospital.

Despite the higher indoor temperature and the higher air exchange rates, the energy requirement can be limited to 15 kilowatt hours per square meter of treated floor area per year (kWh/(m2TFAa).