PDF Publication Title:
Text from PDF Page: 018
Heat Pumps Technology Guide SEAI 3.2.3.2. Horizontal loops Figure 13: Vertical boreholes Horizontal ground loops can be installed in trenches of between 1 m and 2 m deep. Horizontal ground outputs are typically in the range of 5 W/m to 20 W/m of pipe but can be from 1 W/m to 40 W/m. The loops of pipe can be laid out in straight lengths or in coils, known as ‘slinkies’. Horizontal loops usually cost less to install than vertical boreholes, but they require a lot of ground area when providing space heating, usually several times the total floor area of a building being heated. For that reason, horizontal ground loops are typically not used for large systems. The soil type makes a big difference to the amount of heat that can be extracted per square metre. Soils that retain moisture tend to have higher heat outputs than well-draining soils (e.g. installations in dry sand will require several times more ground area than those in wet clay). The specific heat extraction rate from ground loops can typically be between 10 W/m2 and 40 W/m2 of ground area.1 Horizontal trenches depend significantly on rainfall to replenish the heat extracted and cannot usually be installed under hardstanding. Closed loop system design In any closed loop system, the length and diameter of the ground loops are designed to cover sufficient ground area or include a sufficient number of boreholes. The hydraulic system design is also important. The number of pipe loops, the length of each pipe loop, the separation between pipes in the ground and the diameter of the pipe must all be determined to ensure sufficient flow through each loop. The flow must be fast enough to ensure good heat transfer, avoiding laminar flow and minimising pumping losses. Consideration should be given to how the choice of antifreeze affects the design. Some antifreeze products are more viscous than others and the viscosity can increase significantly at the temperatures reached in ground-source systems. The choice of antifreeze products must be considered with regard to environmental risk. There are other types of collectors, such as thermal piles, where pipework is installed in a building’s concrete piles. Advantages Since ground temperatures are lower in summer than air temperatures, ground-source heat pump systems have higher cooling efficiencies than air-source systems. Cooling is supplied directly (where the source system temperature is low and does not need further cooling), or by using a reversible heat pump system. 1 CIBSE TM51 2013b, Table 3.1. 14PDF Image | Heat Pumps Technology Guide
PDF Search Title:
Heat Pumps Technology GuideOriginal File Name Searched:
Heat-Pump-Technology-Guide.pdfDIY PDF Search: Google It | Yahoo | Bing
CO2 Organic Rankine Cycle Experimenter Platform The supercritical CO2 phase change system is both a heat pump and organic rankine cycle which can be used for those purposes and as a supercritical extractor for advanced subcritical and supercritical extraction technology. Uses include producing nanoparticles, precious metal CO2 extraction, lithium battery recycling, and other applications... More Info
Heat Pumps CO2 ORC Heat Pump System Platform More Info
CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com (Standard Web Page)