Heat Pump Systems

MicroChannel technology offers many methods of decreasing this environmental impact by increasing efficiency and reducing chemical inventory, when applied to heat pump systems [274]. 

Conventional chlorofluorocarbon (CFG) and hydrofluorocarbon (HFC) consumption can be completely eliminated by using CO2 as a refrigerant. The 

As discussed in the section on absorbers (Section 7.7.4), falling films used in microchannels have shown potential for ammonia-water systems [279]. The military has shown interest in these absorption systems due to their inherently low electrical requirements and low noise. However, military application requires orientation independence, even more restrictive size requirements, and a heat rejection temperature of 50 °C (120 °F). To address this need, wicking and fractal microchannel technology has been developed that allows orientation independence and control of the liquid film thickness, which in turn controls the majority of mass 

In absorption cycle heat pumps, the compressor is replaced by a smaller pump and an absorption/desorption loop, greatly reducing the necessary power for moving the refrigerant through the system [256]. 

Lexan plate Porous foam Blood flow inlet 

---

This provides another criterion for testing whether a heat-pump system may be cost-effective. A power plant takes three units of to yield one unit of W. Therefore, to provide any incentive for less overall energy use, Q W must be far in excess of 3. 

Heat pumps are particularly suitable for recycling heat energy in the chemical-process industries. For the outlay of an additional fixed-capital expenditure Cec on a heat-pump system, a considerable reduction in the annual heating cost can be effected. 

The payback period in years for a heat-pump system is the additional feed-capital cost Cpc divided by the annual saving on heating costs. This can be written as... 

Schematic of cooling cycle for a heat pump system.

A theoretical discussion of the heat pump appeared in the Journal of the Franklin Institute in I 886. T. G. N. Haldane of Scotland comprehensively pursued the application of heat pumps to the heating of buildings after the mid-1920s. Haldane tested air-to-watcr heat pump systems in his home and concluded that... 

Bose, J. Parker, J. and McQmston, F. (198.S). DesignAIata Manual for Closed-Loop Ground-Coupled Heat Pump Systems. Atlanta American Society of Heating,... 

University of Pennsyh ania. (1975). Proceedings of Workshop on Solar Energy Heat Pump Systems for Heating and Cooling Buildings. University Park, PA University Press. 

A heat pump, which is the opposite of a heat engine, uses work energy to transfer heat from a cold reservoir to a hot reservoir. In households, the cold reservoir is often the surrounding air or the ground while the hot reservoir is the home. For an ideal heat pump system with Qj and T[ referring to the hot reservoir and Q2 and Tj referring to the cold reservoir, the work required is, from the first and second laws. 

Part 2 Ground source heat pump systems (GSHP). 

Design Options for Ground Source Heat Pump Systems [5]... 

This is a conventional water loop heat pump system using a boiler and cooling tower to maintain the water loop temperature (see Measures S15-S17 in Section 6.2). Since outside air handling unit and other terminal devices like unit heaters, wall fin convectors, etc which are often used with this water loop heat pump system need a different operating water temperature than that of the water loop, a plate heat exchanger is used between the primary heating circuit... 

TABLE 6. Comparison of ground source heat pump system types... 

The size of the central heat pump will be smaller when compared to the total installed capacity of heat pumps in the distributed water loop heat pump system. This is because the central heat pump is sized to meet the block load of the entire building. 

Space savings are not expected at the zone level. However space required for mechanical room components may be lower when compared to central heat pump system. 

The first cost is expected to be less than a central heat pump system using ground loop. 

The first cost of this system is expected to be higher than the distributed water loop heat pump system. Addition of a central heat pump and separate piping for hot and cold water should result in higher first cost. 

Figure 15. Conventional water loop heat pump system...

Figure 16. Conventional water loop heat pump system with fresh air heating by water-to-air heat pump...

Lower first cost than the central heat pump systems using ground loop. Disadvantages ... 

Many of the commercially available air-to-water heat pumps have only published operating data in the entering air temperature range above 40 °F. The performance data below 40 °F is readily available for Toyo and Continental units. Capacity and performance data at ambient temperatures below 40 °F are required to be suitable for use in a water loop heat pump system. Commercially available air-to-water heat pumps in the North American market include Continental, Toyo Carrier, Mac Systems and Environmentally Engineered Equipment Inc. 

Figure 19 depicts a water-loop heat pump system where the cooling tower and boiler have been replaced with a ground heat exchanger. This is the most common configuration of ground source heat pump used in commercial buildings. 

CENTRAL MULTIPLE HEAT PUMP SYSTEM WITH GROUND LOOP... 

Figure 22. Central multiple heat pump system with ground loop and primary/secondary pumping...

Caneta Research Inc., 2003. Design Options For Ground Source Heat Pump Systems, Public Works Canada, 22 pp., ftp //ftp.tech-env.com/pub/ultraLow/gshp.pdf. 

Kavenaugh, S.P., 1984. Simulation and experimental verification of vertical ground-coupled heat pump systems, PhD dissertation, Oklahoma State University, Stillwater, Oklahoma. 

Heat extraction from the bedrock by a heat pump system is an environmental friendly heating method where 70% of the heat is taken from the ground. This... 

Here, COPCamot is the maximum heating coefficient of performance, based on a Carnot (ideal) heat pump system operating between low- and high-temperature reservoirs at Tl and Th, respectively. 

The storage is linked to a district cooling system that serves the inner city of Stockholm in Brunkebergs Torg (Figure 90) with natural cold from a lake (Vartan). The surface water is produced from a depth of 35 m and has a temperature ranging from +4 to +6 °C. A heat pump system can lower the supply temperature to +3 °C if required. 

---