Ground water cooling | Archive Titles

Table 1: Breakdown of the cost of a typical open loop borehole system
Description	Cost (£)
General items
Mobilisation, insurances, demobilisation on completion	20,000
Fencing around working area for the duration of drilling and testing	2000
Modifications to existing LV panel and installation of new power supplies for borehole installation	14,000
Trial hole
Allowance for breakout access to nearest walkway (Existing borehole on site used for trial purposes, hence no drilling costs included)	3000
Construct borehole
Drilling, using temporary casing where required, permanent casing and grouting	31,000
Borehole cap and chamber
Cap borehole with PN16 flange, construct manhole chamber in roadway, rising main, header pipework, valves, flow meter	12,000
Permanent pump	13,000
Samples	300
Acidisation
Mobilisation, set up and removal of equipment for acidisation of borehole, carry out acidisation of borehole including removal of all waste, including supply of acid	11,500
Development and test pumping
Mobilise pumping equipment and materials and remove on completion of testing	4000
Calibration test, pre-test monitoring, step testing	3500
Constant rate testing and monitoring	19,000
Waste removal and disposal	6500
Geophysical logging of abstraction borehole at end of testing	3000
Reinstatement
Reinstatement and making good	1500
Total	144,300

Table 2: Cost comparison of conventional and closed loop thermal pile cooling installation
Description	Closed loop thermal pile cooling system		Conventional heating and cooling system
	£	Unit rate (£/m² gifa)	£	Unit rate (£/m² gifa)
HEAT SOURCE
LTHW boiler and flue
LTHW boiler – 30 kW output	6000	2.4	–	–
LTHW boiler – 80 kW output	–	–	15,000	6
Flue system	incl	incl	incl	incl
Gas supply	incl	incl	incl	incl
SPACE HEATING AND AIR TREATMENT
LTHW installation
LTHW pipework distribution in plantroom, pumps, pressurisation unit, water treatment, insulation		7500	3	10,000
CHW installation
Water cooled chiller unit (40 kW load), dry air cooler (90 kW load), pipework distribution in plantroom (excl condenser water), pumps, pressurisation unit, water treatment, insulation	22,000	8.8	–	–
Water cooled chiller unit (90 kW load), dry air cooler (180 kW load), pipework distribution in plantroom (excl condenser water), pumps, pressurisation unit, water treatment, insulation	–	–	34,000	13.6
Condenser water pipework, valves, pumps	16,000	6.4	20,500	8.2
Energy piles
Pipework to 50 piles – total output 50 kW	41,000	16.4	–	–
Header and pipe connections	6000	2.4	–	–
Connection to heat pump from header	8000	3.2	–	–
Heat pump package unit
Water to water heat pump unit incl all associated controls, 63 kW cooling load, 53 kW heating load	34,000	13.6	–	–
Total	140,500	56	79,500	32
The following exclusions relate to the above costs: Secondary heating and cooling circuits within the building, inflation beyond third quarter 2004, main contractor’s overheads, profit and attendance, main contract preliminaries, professional and prescribed fees, contingency and design reserve, VAT.