Heat pumps system using

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... 

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

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

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. 

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. 

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. 

Small to medium size water-to-water heat pumps are considered in this system. Since the primary pumps are common to all the heat pumps, this system may not be ideal for projects where large size multiple heat pumps are used. It is better if dedicated primary pumps are used in the case of large multiple heat pumps. This is discussed in Section 6.4.1. 

In bed 2 the circulation of hot gas from the bed passes through the inter-loop heat exchanger, through the external cooler (which provides some of the useful output of a heat pump system) and back into bed 2. The gas emerging from the bed remains hot until the thermal wave starts to break through, at which time it undergoes a rapid drop in temperature. 

In actual installations these systems have been shown to use about 45 to 50% of the electricity consumed in a similar house with conventional electric resistance heating. It is more efficient than a conventional air-to-air heat pump system, since the heat source is maintained at a constant, known temperature. In moderate cold climates with 6,000 degree-days, an ACEs uses about 25% less electricity than a conventional heat pump with... 

Refrigerators and heat pumps have the same energy flow diagram and have the same components. A domestic air-conditioning and heat pump system as shown in Fig. 6.22 can, therefore, be used as a heat pump in the winter as well as an air-conditioning unit in the summer. Notice that both the domestic air-conditioning and heat pump system share the same equipment. Thus, the investment in the heat pump can also be used for air-conditioning to provide year-round house comfort control. 

In the air-conditioning mode, a domestic air-conditioning and heat-pump system as shown in Fig. 6.22 uses R-134a as the refrigerant. The refrigerant-saturated vapor is compressed from 140 to 700 kPa. Summer ambient air at 30°C is to be cooled down to 17°C. Find the compressor power required, heat removed from the ambient air in the heat exchanger, COP of the system, and mass rate of air flow per unit of mass rate of refrigerant flow. 

It is possible to base heat pump systems on a variety of environmental media seawater, unfrozen rivers, lakes, groundwater, rocks, or sewage. The one proviso for the efficient use of heat pumps is that the point of use must be relatively close to the source. 

Metal hydrides that have a linear dependence of In P vs 1/T can be used in chemical heat pump systems. General equations were developed to relate the thermodynamic variables of the hydrides to the chemical heat pump operating temperatures. A series of hydrides with variable thermodynamic properties were prepared from alloys of composition LaNi5-x Alx (x = 0-1.5). 

Heat Pumps. The use of heat pumps adds a compressor to boost the temperature level of rejected heat. It can be very effective in small plants having few opportunities for heat interchange. However, in large facilities a closer look usually shows an alternative for use of waste heat. The fuel/steam focus of energy use has led to application of heat pumps in applications where a broader examination might suggest a simpler system of heat recovery. 

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