A heat pump is an electrical device that extracts heat from one place and transfers it to another. The heat pump is not a new technology; it has been used in Sweden and around the world for decades. Refrigerators and air conditioners are both common examples of heat pumps.

Heat pumps transfer heat by circulating a substance called a refrigerant through a cycle of alternating evaporation and condensation (see Figure 1). A compressor pumps the refrigerant between two heat exchangers. In one heat exchanger, the evaporator, the refrigerant is evaporated at low pressure and absorbs heat from its surroundings. The refrigerant is then compressed en route to the heat exchanger, the condenser, where it condenses at high pressure. At this point, it releases the heat it absorbed earlier in the cycle.

The collector should be laid about 1 m deep and act as a ground collector on the way to the house. Incoming and outgoing pipes should be separated or insulated from each other.

The heat that is taken from the ground comes from the sun’s rays and as long as the sun shines the ground is recharged during the summer months provided that the installation is correctly dimensioned. The ground operates as a gigantic battery where water conducts new heat into your bore hole.

Rainwater harvesting has a new British Standard for the design of harvesting systems - the BS8515 2009. Many companies have yet to adapt their systems to meet these new regulations, so beware. Drainage is currently covered by the Building Regs. Section H which can affect rainwater harvesting system design eg. soakaway or city drain connections for the tank overflow. Other regulations, enforced by the water supplier, also apply. These are, in England and Wales the Water Supply Regulations 1999 (Water by-laws 2000 in Scotland and Water Supply (Water Quality) Regulations (Northern Ireland) 2002) The essential requirements of the regulations specific to rainwater harvesting are; (1) no cross bonding of rainwater piping with potable supply pipes (2) prevention of backflow to potable water supplies according to CEN EN1717 or air gaps type AA/AB/AC etc (3) the clear marking of rainwater pipes according to WRAS # 9-02-05 and (4) material specifications, where contact with wholesome water is permissible meet the prevailing approved list.

Not for Domestic use but for Commercial purposes, rainwater harvesters qualify for the Government ECA scheme, which provides rainwater harvester grants and allows the whole cost of the harvester to be offsett against tax in the year that it was purchased. See your accountant

At the moment, you can use rainwater for flushing toilets, doing domestic laundry (NOT commercial, nursing home, hospital, etc), washing cars, yards, paths, floors, irrigation, watering livestock, fire extinguishing, and most other non potable purposes except bathing.

Sustainable Urban Drainage (SUDS) is becoming an increasingly used term with planners and developers seeking to mitigate the implications of handling surface water run-off on the local storm water network. This often involves the use of self-draining paving layers together with the installation of pre-formed sub-ground retention tanks, to store surface water for a controlled release into the drainage network.

Defra intends to fund the maintenance of SuDS under the 2010 Flood and Water Management Act. We understand that grants will be provided directly to local authorities based on actual uptake of SuDS by new developments following commencement, and their adoption over time. The requirement to adopt SuDS on new developments is not expected to start until April 2012, and be phased in after that date.

It is said that some local authorities are already active in adopting sustainable drainage. But it could be that the delay in receiving Defra grants for maintenance will discourage other authorities from promoting and adopting SuDS until 2012 or later?

From 1 October 2008 new planning regulations came into force. You can no longer pave over your front garden without considering where the surface water may drain to.

You will NOT need planning permission if a new driveway uses permeable (or porous) surfacing which allows water to drain through, such as gravel, permeable concrete block paving or porous asphalt, or if the rainwater is directed to a lawn or border to drain naturally.

If the surface to be covered is more than five square metres planning permission will be needed for laying traditional, impermeable driveways that do not control rainwater running off onto roads.