Solar Heat Energy Demonstrator

Google Earth

Google Earth

To Do:

• Review designs and calculate loads
• Produce schematic of proposed design
• Detailed design of pipework and equipment

Aims

The aim of the project is two-fold. Primarily it is to provide better heating for the building using low carbon heat, bringing the building up to a suitable level of heating to be passed on to the next occupants. However, the project is also been run as a laboratory test to work out the best practices and installation choices, to maximise in-use efficiency of CO2 heat pump technology, and work out it's place in the renewables landscape for the future.

Requirements

Following initial site meetings the following requirements have been set:

• Installation of CO2 air source heat pump(s)
• Low use domestic hot water
• Central heating to 10 office spaces
• Office spaces to be fitted with a selection of heat emitter types
• System to be flexible enough to allow different heating strategies to be tested
• System must be of a standard to be handed over to the next building occupants
• System must allow for the optional use of fan convectors as final stage to heat the main area and lower return temperatures
• System to be provide real-time operational data and allow details adjustment of settings and controls logic

Topology

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{"text":"Buffer Store","key":-2,"loc":"-400 20","figure":"Cylinder1","size":"60 140"},
{"text":"Central Heating Zone 1","key":-3,"loc":"-130 -80","group":-6},
{"text":"Central Heating Zone 2","key":-4,"loc":"-130 0","group":-6},
{"text":"HIU for Domestic Hot Water Only","key":-5,"loc":"-130 -160","group":-6},
{"isGroup":true,"text":"Loads","key":-6,"loc":"-130 -80","dash":[4,4]},
{"text":"Main Area Fan Convector","key":-7,"loc":"-290 210","figure":"ManualOperation"},
{"text":"Pump","key":-8,"loc":"-290 -80","figure":"Ellipse","size":"60 60"},
{"text":"Valve","key":-9,"loc":"-130 120","figure":"Diamond"},
{"text":"Pump","key":-10,"loc":"-600 70","figure":"Ellipse","size":"60 60"}
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{"from":-2,"to":-10,"points":[-430,43.333333333333336,-440,43.333333333333336,-500,43.333333333333336,-500,70,-560,70,-570,70]}
]}

Heat Pump Selection

Mitsubishi Electric QAVG 40kW CO2 Air Source Heat Pump

Selection

The selected heat pump is a Mitsubishi Electric QAVG 40kW CO2 Air Source Heat Pump.

Specifically designed for commercial sanitary hot water application, where gas boilers, combined heat and power systems (CHP) or electric water heating have been traditionally utilised, the QAHV provides a low carbon solution for hospitals, hotels, leisure centres and student accommodation. Utilising the natural and stable refrigerant CO2 (R744), the environmentally clean solution enables compliance to strict local planning laws and boosts BREEAM points. Compounded by the increasing decarbonisation of the electrical grid and the UK’s commitment to Net Zero 2050, the QAHV provides a high efficiency, low carbon hot water delivery solution with leaving water temperature up to 90°C.

Documentation

QAHV_6PP_AW_v2
QAHV-N560YA-HPB_Service_Manual
QAHV-N560YA-HPB_Install_Manual
QAHV-N560YA-HPB-PI-SHEET

Sizing

Bivalent Systems for Heat Networks

The following designs show the impact of a single 40kW heat pump on various numbers of properties. This is unrelated to the SHED, however is shown in order to give the reader a feel for the impact of even a single heat pump on real-world loads.

Each property is 2 bedroom 3 person, and 4kW heating load.

Topping up boilers are included to achieve peak loads.

Caption text

Properties	% Heat Pump	Design Link
20 x 2B3P	99.9%	https://hw7.ddns.net/ui/hndesign?loadCID=QmNg4trTmoxkD35qj4eBWd1exKwKfbVpP3jRNgEQwZn4qB
30 x 2B3P	94.6%	https://hw7.ddns.net/ui/hndesign?loadCID=QmXz5H1sdV5F1juQrQc71PLjdWCPWkHhqHkitGbC8o8B9z
40 x 2B3P	83.6%	https://hw7.ddns.net/ui/hndesign?loadCID=QmPgBB6jSXehwP2ZYp7LcZNQeEyXggQM4FPgcgdQWQgZVc

Bivalent40kw

This graph shows how the vast majority of load (for 2021) is driven by heat pumps (blue & orange), with boilers (green) used to top up.