Social for Tall Apartment Blocks
Islington, London

Inspace is a social and affordable housing specialist, building over 1,600 new homes a year in a range of projects. Northpoint Islington is a development of 47 flats arranged over six storeys. Fifteen of the flats are for an RSL client, the balance of 32 being available for private buyers. The development was required by the local planning authority to produce more than 10% of its energy on site from renewable energy sources.

As the development was a taller building Viridian Solar had to calculate the amount of collector required for all floors, the design team calculated 2.4 sq m for each of the 32 flats selected for solar heating.

The most common approach to solar heating design would be to link dedicated solar panels to hot water cylinders in each flat. The problem was that the large number of insulated pipes (two per flat) would not fit in the space available for risers, and the design team disliked having a number of penetrations through the roof. Also, heat loss from the pipes would increase with the greater the distance travelled, so occupants on the lower floors would suffer. A communal heating system would normally be the answer, but in this case it produced more problems, since there was no space for a plant room, and the client disliked the idea of metering heat to apartments.

Viridian Solar has developed a solar heating system - Cirrus that provides developers with all the benefits of a communal solar system without having to give up a large area for a plant room, enabling each flat to have its own individual heating system. Panels on the roof of the building are grouped to serve a set of flats. A single pair of pipes run from the solar panels and down the service riser. Heated fluid from the solar panels is circulated to the flats in a loop on each floor. Flow balancing components ensure a fair distribution of heat between every dwelling.

The energy savings are optimised compared to individual solar systems due to ‘load sharing’- for example if the residents of one flat are on vacation, the other residents get to use their allocation of the solar panel area. The number of solar panels needed was reduced from 32 to 25 using this system. By integrating this solar hot water heating system into the housing at Northpoint, 5.2 tonnes/year of carbon emissions was avoided, saving 30,000 kWh/year of energy.

For more information on how solar hot water heating can be integrated into a new housing development, please contact our member companies who can assist with design, supply and installations.

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