CN110998193A

CN110998193A - Zone cooling system

Info

Publication number: CN110998193A
Application number: CN201880043684.XA
Authority: CN
Inventors: 符阳光
Original assignee: Space Pte Ltd
Current assignee: Singapore Energy Innovation Development Co ltd
Priority date: 2017-04-28
Filing date: 2018-04-27
Publication date: 2020-04-10
Also published as: SG11201909790UA; WO2018199848A1; PH12019502390A1

Abstract

A district cooling system for providing a supply of cooling water to a plurality of buildings, the system comprising: a chiller in fluid communication with the plurality of buildings; each of the buildings belongs to at least one of a plurality of categories; wherein each of the categories is defined by a respective peak demand over a different time period.

Description

Zone cooling system

Technical Field

The present invention relates to zone cooling systems, and in particular to efficient devices for integrated general purpose zones.

Background

For a typical air conditioning system, two energy circuits are required to achieve cooling. The two circuits exchange energy rather than a heat transfer medium. One circuit (technically referred to as the "evaporation" and cooling process) is to recycle cold energy to the end of use and in the process to carry away the heat generated in the room. The heat transfer medium for this circuit is a refrigerant or water. Another circuit (technically referred to as the "condensation" and heat rejection process) is to reject heat rejected from the room to the atmosphere through the work done by the compressor. The heat transfer medium for this circuit is air or water.

For residential development projects, direct expansion (DX) air-cooled systems, which typically include an external compressor and fan (outdoor condensing unit) and a single household level internal fan-coil unit (FCU), have become popular systems. In the case of such a system, heat continuously accumulated in the room is discharged to the atmosphere via the outdoor condensing device using ambient air as a heat transfer medium, and thus is referred to as an air-cooling type system. DX air-cooled systems utilize refrigerant as the heat transfer medium to circulate the cold energy between the FCU and the outdoor condensing units. One disadvantage of DX air-cooled systems is that the outdoor condensing units cannot be located too far from the FCU due to the small size of the compressor.

Larger air conditioning systems utilize water as a heat transfer medium to remove heat accumulated in the living space to the outside, and are therefore referred to as water-cooled systems. Unlike air, water is a more efficient heat transfer medium because of its superior thermal conductivity (sensible heat) and ability to absorb large amounts of heat by converting itself to steam (latent heat). In addition, large air conditioning systems utilize water as a medium to circulate cold energy between a point of generation (a water chiller) and a point of use (an air handling device or a chilled water fan coil). Unlike the smaller DX air-cooled systems, there is no longer a coverage distance constraint. Circulating water over long distances is also more economical because water is less expensive than refrigerant. Therefore, water-cooled cooling water systems are favored for large non-residential development projects, such as offices, hotels, and retail outlets, where the cooling demand continues to be high.

In each large development project, a typical chilled water system includes central chilled water generation and distribution (water chiller, cooling tower and pump) and end user devices (air handling, fan coil, and pre-chilled air devices). The cooling water flows from the generating device (usually located in the basement of the building) to the end-use points located in various parts of the building. The cooling water as a heat transfer medium provides cold energy and also takes away heat in the space. During this process, the cooling water becomes warmer and flows back to the chiller to be re-cooled and recirculated.

Instead of each development project having its own chiller, it has become increasingly popular to cool groups of buildings using one or more central chillers (also known as District Cooling Systems (DCS)).

Disclosure of Invention

In a first aspect, the present invention provides a district cooling system for providing a supply of cooling water to a plurality of buildings, the system comprising: a chiller in fluid communication with the plurality of buildings; each of the buildings belongs to at least one of a plurality of categories; wherein each of the categories is defined by a respective peak demand over a different time period.

In a second aspect, the present invention provides a local area cooling system for distributing cooling water to buildings within a local jurisdiction, the system comprising: a network of chiller units, each chiller unit located near one of the buildings; each of said chiller units being arranged to provide a supply of cooling water to equipment within a respective building; wherein the chiller units are in fluid communication with each other.

In a third aspect, the present invention provides a district cooling system for providing a supply of cooling water to a plurality of buildings, the system comprising: a chiller in fluid communication with a plurality of buildings, wherein the plurality of buildings includes one or more buildings belonging to a first category and one or more buildings belonging to a second category; wherein each of the categories is defined by a respective peak demand over a different time period, and wherein the peak demand of the first category supplements the peak demand of the second category to optimize the system.

According to an aspect of the invention, the local area cooling system according to the invention may be at least partly used for:

(1) the energy efficiency of the home is improved by changing the less efficient air-cooled DX device to a water-cooled system.

(2) The family refrigeration load is aggregated to implement a water-cooled system, allowing the households in one or both residential areas to be supplied by a single water-cooled chilled water unit. A chilled water service similar to a central chilled water system will be provided to the home.

(3) Ensuring chilled water is considered a new municipal utility for both businesses and residences. Thus, since a paid air conditioning service will be provided, it is necessary to ensure reliability of supply to residential residents.

In one embodiment, the local area cooling system may include interconnected chiller units built on a roof of, for example, three, four, or five residential areas, and may be grouped to provide a central refrigeration supply.

Benefits of this embodiment may include:

may be implemented in a region of a pure or primarily residential development project;

central refrigeration with interconnected chiller units can significantly improve the reliability and efficiency of the cooling system.

Higher energy efficiency per household and lower energy consumption/cost can be achieved compared to traditional decentralized device systems.

Community facilities within or near the group, such as vendor centers and outdoor community spaces, may also benefit from a cooler and more pleasant environment with the system.

According to a second aspect of the invention, a District Cooling System (DCS) may be implemented in a region other than a residential/integrated use development project. DCS can supply cooling water to areas with relatively high refrigeration demand (typically peaking during the day and weekdays), which can be extended to nearby residential jurisdictions where refrigeration demand typically peaks during the evening and weekend. This reverse cycle demand from residential and non-residential development projects allows for a shared cooling system investment to gain economic value to be shared by all stakeholders.

Drawings

It will be convenient to further describe the invention with reference to the accompanying drawings which illustrate possible arrangements of the invention. Other arrangements of the invention are possible and consequently the particularity of the accompanying drawings is not to be understood as superseding the generality of the preceding description of the invention.

FIG. 1 is a schematic view of a zone cooling system according to one embodiment of the present invention;

FIG. 2 is a plan view of a localized area cooling system in accordance with an embodiment of the present invention;

FIG. 3 is an elevation view of a localized area cooling system in accordance with an embodiment of the present invention;

FIG. 4 is a schematic view of a zone cooling system according to another embodiment of the present invention.

Detailed Description

The invention may therefore comprise a district cooling system arranged to serve different categories of use, the categories being defined by the period of cooling water demand.

In this way, the DCS may have a capacity determined by the greater peak demand of the various classes.

Accordingly, fig. 1 shows an improved zone cooling system (DCS) 5. Here, a decentralized district cooling unit 10 supplies cooling water to a series of buildings 30, 40 via a network of pipes 15. In particular, each building comprises a heat exchanger 25, 35 for exchanging heat within the building 30, 40 for final return of water 20.

The DCS 5 according to the present invention is arranged to serve different classes of buildings, including commercial buildings 30 and residential buildings 40. On this basis, the cooling water demand of the commercial site 30 is greatly increased during the day, particularly on the working day, while the cooling water demand of the residential site 40 is decreased. This demand is reversed during weekend and evening periods, whereby the demand of the home attribute 40 increases. The time of peak demand for each of these categories is then determined by the respective time period.

The DCS may be designed for peak demand for experience during the evening/weekend cycles or the day and weekday cycles. Thus, the highest peak demand in both schemes will accommodate the opposite cycle demand. This is advantageous to optimize DCS resources that may not be fully utilized in any cycle. The DCS may also provide the opportunity to reduce its capital expenditure compared to conventional zone cooling systems that provide two peak demands for each cycle separately rather than as an alternative.

To this end, the infrastructure within the DCS 5 in accordance with one embodiment of the invention will include monitoring of peak refrigeration demand and peak power demand. Thus, the application of the integrated use of DCS 5 provides benefits beyond those experienced in prior art systems.

Fig. 2 and 3 illustrate another aspect of the present invention. Here, the local area cooling system 45 operates at a local level. As shown in fig. 2, the four

buildings

50A, 50B, 50C, 50D include

respective chiller units

55A, 55B, 55C, 55D for providing cooling water to the respective buildings. However, the local area cooling system 45 includes a fluid connection 60 between each of the

chiller units

55A, 55B, 55C, 55D, thus benefiting from demand variations between buildings within the local area to optimize the system according to specific needs. It should be understood that the local area cooling system 45 may be a fully residential, fully commercial, or general purpose system, whereby demand within the local system 45 may fluctuate based on recognized periods.

It should be understood that in various embodiments, the chiller may be located at mid-height, above ground, or below ground.

The partial area elevation view shown in fig. 3 shows the

chiller units

55A, 55B of both

buildings

50A, 50B, thereby illustrating the distribution of cooling water to the various occupied units/apartments 85. Each apartment 85 includes a distribution pipe 90 and a row of cooling water fan coil arrangements 95 that receive cooling water, thereby achieving energy efficiency and CAPEX efficiency. In determining the number of chiller units for a local area cooling system, this will be a function of the number of residential buildings in the respective local jurisdiction or group for which the local area cooling system provides cooling. Another relevant factor may be the equivalent capital expenditure of an equivalent decentralized cooling system compared to the capital expenditure of a chiller of a local area cooling system that provides similar cooling capacity for the same residential building. Given that the localized area cooling system according to the present invention may be more capital efficient, the chiller to building ratio may be less than 1: 1.

In one embodiment, for a group of 5 residential buildings, 3 chiller units can provide the same cooling effect as a comparable system utilizing a decentralized system. The 3 chiller units may be located on 3 of the 5 residential buildings located near the center of the cluster, for example, to facilitate the transport of cooling water.

The cooling water is shared between buildings by the networked piping 60, so each of the

chiller units

55A, 55B, 55C, 55D serves each building within the local area cooling system, as compared to the inefficiency of chiller units located within a single building.

One advantage of this approach includes that the chiller for a particular building must accommodate the potential needs of that building, whether or not that need is fulfilled. With a distribution system for a local area cooling system, peak demand can be managed among all chiller units in the local system, thereby better managing the demand of one building with lower demand of another building in the area cooling system, so that the infrastructure as an integrated network can better meet the demand required. In the event that one of the chiller units is not in use for maintenance or other reasons, the remaining chiller units may be configured to provide cooling energy to the buildings in the area.

Figure 4 is a schematic diagram of a residential development project with a single local area 105 within a larger town 100. Town center 110 may include a network 115 of chiller units fluidly connected by network piping 120 to serve a commercial jurisdiction within the town center. This will therefore function as a conventional zone cooling system. However, the district cooling system in town centres may also have communication 125 with heat exchangers in neighbouring dwellings 130, thus having the benefit of application of the integrated use of the district cooling system according to an aspect of the invention. A local area cooling system similar to that described with reference to fig. 2 and 3 may be present within the residential area. The local area 135 may or may not be in communication with a regional cooling system in the center of the town. The embodiment of fig. 4 thus has the possibility of integrating a general-purpose DCS system according to one embodiment of the invention with a local DCS system according to another aspect of the invention. Thus, the benefits of efficiency achieved by integrated use DCS can be enhanced by the benefits of local DCS according to another embodiment of the invention, thereby further optimizing the capital expenditure for cooling water distribution.

When considering the business model of the present invention, the charging for access area cooling may be based on the time of use and size of the home device. A chronograph watch may be installed for each device of the home. Rates may fluctuate according to periods of time when peak demand is different.

Thus, the cost of the access system may be a function of the time of use and/or size of the home device. To record such usage, a plurality of meters may be connected to each device within each building, the meters being arranged to record the time of use.

Claims

1. A district cooling system for providing a supply of cooling water to a plurality of buildings, the system comprising:

a chiller in fluid communication with the plurality of buildings;

each of the buildings belongs to at least one of a plurality of categories;

wherein each of the categories is defined by a respective peak demand over a different time period.

2. The district cooling system of claim 1, wherein the capacity of the chiller is determined by the category with the highest peak demand.

3. The district cooling system of claim 1 or 2, wherein the categories include commercial use and residential use.

4. The district cooling system of claim 3, wherein the time period corresponding to the category of commercial use comprises between 9 am and 5 pm on a weekday.

5. The district cooling system of claim 3 or 4, wherein the time period corresponding to the category of residential use comprises between 5 pm and 9 pm on a weekday and/or on a weekend.

6. A local area cooling system for distributing cooling water to buildings within a local jurisdiction, the system comprising:

a network of chiller units, each chiller unit located near one of the buildings;

each of said chiller units being arranged to provide a supply of cooling water to equipment within a respective building;

wherein the chiller units are in fluid communication with each other.

7. The localized area cooling system of claim 6, wherein each chiller is located within the building.

8. The local area cooling system of claim 6 or 7, wherein the number of chiller units in the network is less than the number of buildings in the local jurisdiction.

9. The local area cooling system of any one of claims 6 to 8, wherein the aggregate capacity of the chiller is in the range of 100% to 150% of the aggregate peak demand of the plurality of buildings.

10. The localized-area cooling system of any one of claims 6 to 9, further comprising a fluid connection to place the localized-area cooling system in fluid communication with a second localized-area cooling system.

11. A zone cooling system comprising a plurality of the localized zone cooling systems of any one of claims 6-10 in fluid communication with one another.

12. A zone cooling system, wherein the zone cooling system according to any one of claims 1 to 5 is in fluid communication with the localized zone cooling system according to any one of claims 6 to 10.

13. A district cooling system for providing a supply of cooling water to a plurality of buildings, the system comprising:

a chiller in fluid communication with the plurality of buildings;

wherein the plurality of buildings includes one or more buildings belonging to a first category and one or more buildings belonging to a second category;

wherein each of the categories is defined by a respective peak demand over a different time period, and

wherein the peak demand of the first category supplements the peak demand of the second category to optimize the system.

14. The zone cooling system of claim 13, wherein the access cost is a function of a usage time and/or a size of the home device.

15. The district cooling system of claim 14, further comprising a plurality of meters connected to each device within each building, the meters arranged to record usage time.