Wastewater heat recuperator

Abstract

This utility model relates to energy-saving technologies in the field of hot water supply and can be used to recover waste heat from gray water in domestic hot water systems, particularly under sinks and other sanitary fixtures in residential and commercial buildings. The technical result of this utility model is the maintenance of energy efficiency during long-term operation and in frequent intermittent use modes, while reducing the complexity of maintenance.The technical result is achieved in that the wastewater heat recuperator, containing a drain channel for receiving and discharging wastewater, made in the form of a sanitary siphon with a glass, equipped with a coil heat exchanger for recuperating the heat of the wastewater, made from a corrugated steel tube, which is equipped with an inlet and outlet pipe for supplying and discharging cold water, is characterized in that it additionally contains a hydrophobic coating applied to the surface of the coil heat exchanger on the wastewater side, thermal insulation applied to the outer surface of the drain channel, as well as a drain valve installed in the body of the drain channel.

Description

[0001] The utility model relates to energy-saving technologies in the field of hot water supply and can be used to utilize the waste heat of "gray" wastewater in domestic hot water supply systems, in particular under sinks and other sanitary fixtures in residential and administrative buildings.

[0002] A heat exchange device is known for the recovery of heat from wastewater (see patent CN No. 200962004, IPC F28D 1 / 047, published on October 17, 2007), which includes a heat exchange chamber and heat exchange tubes and has the following design features: in the upper part of the heat exchange chamber there is an inlet for “gray” wastewater from showers and baths, in the lower part of the heat exchange chamber there is a pipe for draining wastewater, inside the heat exchange chamber there is a heat exchange tube having pipes for supplying and draining the coolant.

[0003] A plumbing drain with a heat exchanger is known (see patent EP No. 2453194, IPC F28D 7 / 02, published on 16.05.2012), including a drain channel equipped with a heat exchanger for recovering heat contained in used water after a shower, the heat exchanger includes a tube, preferably made of metal, placed in the drain channel and connected to a cold water channel, the heat exchanger has an elongated shape, the tube is formed in such a way that it consists of a plurality of parts, the length of which at least corresponds to the length of the drain channel.

[0004] Also known is a shower installation with wastewater energy recovery (see patent FR No. 2868796, IPC E03C 1 / 00, published on 14.10.2005), including means for supplying hot water and means for supplying cold water, means for receiving and discharging wastewater, as well as an energy recovery device with a heat exchanger located at the level of the means for receiving and discharging wastewater, capable of recovering the heat of the latter for transferring it to the means for supplying cold water.

[0005] These devices are marketed as bathtub and shower enclosure units. Their disadvantages include their size and weight, which prevent them from being installed under sinks. It should be noted that these designs are designed specifically for foreign water supply and drainage systems and cannot be directly used in standard Russian water supply and drainage systems without significant modification.

[0006] The closest in technical essence and the achieved result is the utility model "Wastewater Heat Recuperator" (see patent RU 216381 U1, IPC E03C 1 / 22, published on 31.01.2023), containing a drain channel for receiving and discharging wastewater, equipped with a coil heat exchanger for recovering the heat of the wastewater, which is equipped with an inlet and outlet pipe for supplying and discharging cold water, the drain channel is made in the form of a plumbing siphon with a glass, and the coil heat exchanger is made of a corrugated steel tube.

[0007] The disadvantages of this system include reduced energy efficiency during long-term operation and frequent intermittent use, as well as complex maintenance. The reduced energy efficiency during long-term operation is due to the gradual formation of grease and mineral deposits on the outer surface of the coil heat exchanger, leading to increased thermal resistance. Low energy efficiency in frequent intermittent use is due to the rapid cooling of the accumulated wastewater volume inside the recuperator, necessitating preheating of this volume, preventing the achievement of the design efficiency during short-term but frequent use, which is typical for some hot water supply systems in administrative buildings.The complexity of service maintenance is due to the lack of a structurally provided possibility of completely emptying the device during installation and repair.

[0008] These shortcomings necessitate the creation of an improved heat recuperator for grey wastewater that ensures long-term energy efficiency during operation, reduces heat loss through the outer surface of the housing, and simplifies servicing of the device while maintaining compact dimensions and weight.

[0009] The technical result of the utility model is the preservation of energy efficiency during long-term operation and in modes of frequent periodic use with a reduction in the complexity of servicing.

[0010] The technical result is achieved in that the wastewater heat recuperator, containing a drain channel for receiving and discharging wastewater, made in the form of a plumbing siphon with a glass, equipped with a coil heat exchanger for recuperating the heat of the wastewater, made from a corrugated steel tube, which is equipped with an inlet and outlet pipe for supplying and discharging cold water, is characterized in that it additionally contains a hydrophobic coating applied to the surface of the coil heat exchanger on the wastewater side, thermal insulation applied to the outer surface of the drain channel, as well as a drain valve installed in the body of the drain channel.

[0011] Figure 1 shows a schematic diagram of a wastewater heat recuperator, where: 1 - body (drain channel), 2 - heat-insulating layer, 3 - sealing input, 4 - corrugated coil heat exchanger, 5 - inlet pipe for cold water supply, 6 - outlet pipe for cold water discharge, 7 - drain valve, 8 - hydrophobic coating, 9 - wastewater discharge pipe, 10 - wastewater inlet pipe, 11 - glass.

[0012] Detailed design description.

[0013] The wastewater heat recovery unit comprises a drain channel 1, which serves as the unit's housing. Housing 1 is equipped with a wastewater inlet and outlet pipe, 10 and 9, respectively, and is also provided with a removable cup 11 for access to the internal volume. The outer surface of housing 1 is covered with a layer of thermal insulation 2.

[0014] The housing 1 contains a steel coil corrugated heat exchanger 4, passing through the housing 1 through sealing entries 3. The heat exchanger 4 is coated on the wastewater side with a hydrophobic coating 8.

[0015] Heat exchanger 4 is equipped with inlet and outlet pipes for supplying and discharging cold water 5 and 6, respectively.

[0016] A drain valve 7 is also installed in housing 1, designed to hermetically close the drain hole in normal operating mode.

[0017] The wastewater heat recuperator is mounted under a sanitary fixture, in particular under a sink, instead of a sanitary siphon, preserving its function of creating a water seal, and operates as follows.

[0018] During water consumption hours, when a consumer uses a sanitary fixture, particularly a sink, for household needs, a flow of gray wastewater forms at the entrance to wastewater inlet pipe 10. Through wastewater inlet pipe 10, the gray wastewater enters housing 1. The gray wastewater entering housing 1 creates a volume of liquid that acts as a water seal and ensures heat accumulation. From housing 1, the wastewater displaced by the incoming flow is discharged into the sewer system through wastewater outlet pipe 9.

[0019] Cold water flowing to the mixer tap enters the corrugated coil heat exchanger 4, located in housing 1, through cold water inlet pipe 5. During operation, the corrugated coil heat exchanger 4 is immersed in the grey wastewater. Passing through the heat exchanger, the cold water absorbs the wastewater's heat, causing the cold water temperature to increase and the wastewater temperature to decrease. Heated by the wastewater heat, the cold water exits the corrugated coil heat exchanger 4 through the cold water outlet pipe 6 and is directed to the mixer tap.

[0020] Supplying heated cold water to the mixer causes the temperature of the mixture in the mixer to rise, forcing the consumer to reduce the consumption of hot water to maintain a comfortable temperature of the mixture, creating an energy-saving effect.

[0021] Hydrophobic coating 8 on the surface of the corrugated coil heat exchanger 4 reduces the adhesion of fatty and mineral particles entering with wastewater. Coating 8 reduces the rate of deposit formation on the heat exchanger surface, preventing an increase in thermal resistance and a decrease in the energy efficiency of the recuperator during operation.

[0022] Thermal insulation layer 2 on housing 1 reduces heat loss to the environment, allowing the sanitary faucet to maintain high efficiency even with frequent, intermittent use. This is achieved by extending the storage time of accumulated heat in the gray water stored in housing 1. This allows for heated cold water to be available immediately upon initial use of the sanitary faucet, without the need for preheating the gray water in housing 1.

[0023] Maintaining an elevated temperature of wastewater in the volume of housing 1 during periods between cycles of use of the sanitary device helps to reduce the likelihood of the precipitation of some polluting components from the “gray” wastewater and their subsequent deposition on the surface of the heat exchanger 4, which additionally helps to maintain its thermal characteristics during operation.

[0024] Access to coil heat exchanger 4 for periodic cleaning and renewal of hydrophobic coating 8 is provided by disconnecting bowl 11 from housing 1. When draining the recuperator, drain valve 7 is used. It opens and allows for controlled removal of the static liquid volume from housing 1 when tilted or inverted. Drain valve 7 also helps eliminate air locks during initial filling of the system, which reduce the efficiency of the unit by reducing the contact area between wastewater and heat exchanger 4.

[0025] Thus, the wastewater heat recovery unit implements the function of a plumbing siphon and ensures the effective return of heat from the wastewater to cold water. The combination of distinctive features ensures the long-term preservation of the energy efficiency of the device by reducing contamination of the heat exchanger, reducing heat loss of the accumulated volume of wastewater and simplifying maintenance.

Claims

A wastewater heat recuperator comprising a drain channel for receiving and discharging wastewater, made in the form of a sanitary siphon with a glass, equipped with a coil heat exchanger for recuperating wastewater heat, made from a corrugated steel tube, which is equipped with an inlet and outlet pipe for supplying and discharging cold water, characterized in that it additionally contains a hydrophobic coating applied to the surface of the coil heat exchanger on the wastewater side, thermal insulation applied to the outer surface of the drain channel, and also a drain valve installed in the body of the drain channel.

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