Technical data

14
Is a Greenstar Plus Hybrid system
suitable for the property?
It is essential that Hybrid systems are designed to operate
efficiently in order to meet the building heating needs and
the expectations of the customer. In order to achieve this,
the following design activities must be completed prior to
the installation:–
•
Pre-design assessment
Pre-requisite: Determining the suitability of a Hybrid
system for the building based on the customer's
requirements, expectations and building type.
•
Detailed design
Complete building heat loss calculations and domestic
hot water usage assessment.
•
Specification
Select the Hybrid system based on the detailed design.
Calculate and communicate the predicted energy use and
running costs of the system to the customer.
Heat loss
The total heat loss of the property is calculated from the
addition of fabric and ventilation heat losses. Fabric heat
loss is the transmission of heat by conduction through
the building structure, i.e. windows, walls, roof and floor.
Ventilation heat loss is heated air escaping from the
property and being replaced by cold air from the outside.
Calculating the heat loss of the property
It is essential to accurately calculate the heat loss of the
property to ensure correct sizing of the Hybrid system. The
heat loss is dependent on the construction of the building,
room sizes, external and internal design temperatures and
air change rates. The heat loss calculations should satisfy
the requirements of BS EN 12831.
Estimating heat loss
Estimating the heat loss of the building is useful in
determining the suitability of a Hybrid system. However,
assumptions based on floor area (e.g. 50 W/m
2
for
new build etc.) and SAP (the Government's Standard
Assessment Procedure) should not be used for the detailed
design and specification stage. It should be noted that the
heat loss for non-standard properties i.e. buildings with
large areas of glazing, high ceilings, log burners etc. or
properties in exposed locations may deviate significantly
from any rules of thumb.
In existing properties, boilers are often oversized and
should therefore not be used to determine the actual heat
requirements of the house.
However, estimates may be made on the basis of the
existing energy consumption of the space to be heated.
This brochure does not cover all the necessary details
to calculate the heat loss. The information given here
is provided to remind the heating system designer and
installer of the process and considerations.
Worcester design service
Worcester’s design team offers design support across all of
the Worcester, Bosch Group product range. The design
team produces technical drawings and provides
specification advice for a range of customers; all of our
team are authorised SAP assessors and hold an IDHEE
Domestic Heating Design Certificate. Worcester
provides a range of indemnified design solutions
in support of our core range of Greenstar gas-
and oil-fired boilers, Greenfloor heating and a
growing portfolio of renewable technologies – including
Greenskies solar thermal panels as well as Greenstore
ground source and Greensource air source heat pumps.
The design service for Worcester Greenstar Plus Hybrid
System includes calculations for:
•
Estimated annual running costs
•
Estimated annual CO
2
savings
•
Estimated annual cost savings.
For more information on the suitability of hybrid for your
property visit www.worcester-bosch.co.uk
For information and guidance on planning permission
for split air to water heat pumps visit
www.energysavingtrust.org.uk