GB2188413A

GB2188413A - Central heating system

Info

Publication number: GB2188413A
Application number: GB08703233A
Authority: GB
Inventors: Philip Arthur Richard Stukley
Original assignee: Individual
Current assignee: Individual
Priority date: 1986-02-13
Filing date: 1987-02-12
Publication date: 1987-09-30
Also published as: GB8603511D0; GB8703233D0

Abstract

A fresh air central heating system is described which uses cool air about 28 DEG F to provide house warmth, hot water and filtered air. A heating control unit (14) uses solid state thyristors to control the operation of the heating system. Air is inducted through a duct (10) by a centrifugal fan (5), a washable filter (17) and past an electronic shutter (18). An electric battery heater (12) is coupled to a control panel (14) which in turn is connected to a thermistor. The control unit (14) includes a temperature controller (24) which senses the temperature of the thermistor and which controls operation of the battery heater (12) to heat the inducted air. A frost thermostat (30) can be fitted to the control unit (14) to override the time clock in the event of freezing temperatures. <IMAGE>

Description

SPECIFICATION Central heating system The present invention relates to a central heating system particularly, but not exclusively for use in a domestic environment.

Ideally a central heating system should satisfy a number of desirable criteria in addition to being easy to install and economic to run. It should require a minimum of parts and should when installed be unobstrusive and aesthetic. It should also minimise condensation and provide a supply of fresh warm air and also provide constant hot water. Furthermore the central heating system should have a control unit which is easy to operate and which efficiently controls the heating to minimise power comsumption.

Many central heating systems claim to satisfy some of these criteria but it is believed that no single central heating system meets all of these criteria. Moreover, in some cases the requirements seem contradictory, fresh air if moist, can result in condensation and for an efficient operating of central heating systems it is believed necessary to minimise air flow because of associated heat transfer.

An object of the present invention is to provide an improved central heating system which obviates or mitigates the aforesaid disadvantages.

This is achieved by providing a forced air central heating system which uses cool fresh filtered air to combine whole house warmth, hot water and a fresh clean atmosphere and providing a heating control unit incorporating solid state switches for conveniently and efficiently controlling the central heating system.

In one aspect of the present invention there is provided a central heating system comprising duct means having a filter and fan means for blowing cool fresh air through said filter, said cool fresh air being efficiently heated to provide a source of hot warm air.

Conveniently said central heating system is used to also provide hot water.

In another aspect of the invention there is provided apparatus for controlling the efficiency of a central heating system, said apparatus comprising a control unit having temperature sensing means, solid state switch means being responsive to output signals from said temperature sensing means, said heating means coupled to an output of said solid state switch means for controlling the operation of said heating means in response to signals from said temperature sensing means.

Conveniently said solid state switch means are thyristors and said temperature sensing means is a thermistor.

The thyristors are used to operate electrical battery heaters and the thermistors accurately sense temperatures with the use of a temperature controller and room thermistor. The thyristors permit high speed and efficient switching of the electric battery so that 'run-down' and 'start-up' times are minimised and heating and efficiency is maximised.

These and other aspects of the invention will become apparent from the following description when taken in combination with the accompanying drawings in which: Figure 1 is a perspective and partly broken away view of part of a control system in accordance with an embodiment of the invention; and Figure 2 is a perspective view of a ground floor of a house with a central heating system according to the invention installed.

Reference is made to Fig. 1 of the drawings which illustrates a heating system air intake duct 10 having an electric battery heater 12 coupled to a control panel 14. The control panel 14 has inputs coupled to a thermistor, not shown, setting the switching threshold of the heating system. The duct 10 has a centrifugal fan 5 for providing four air changes an hour and for continuously inducting fresh cool air for heating the house. The inducted air is not recirculated. Cool air about 28"F is extracted by the fan through a louvered bird grille 16, a washable filter 17 and past an electronic shutter 18, which is closed at night to avoid wind draught. The air is passed through duct 10 and other interconnected ducts 20 as seen in Fig. 2 to ceiling grilles 22 in each room shown.

The control unit 14 uses thyristors to operate the battery heater 12 and accurately senses temperatures using a temperature controller 24 and a room thermistor. The control unit 14 also includes a time clock for automatic operation and a manual unit for controlling heating outside the pre-set times of the time clock. The fan motor is protected by overloads and a run-on timer is fitted to the fan to operate for a pre-set time on the timer to enable the heater battery to cool down after the system is switched off.

The thyristors permit rapid and efficient switching of the battery heater 12 to maximise efficiency and minimise heating costs and long run-down times and start-up times are minimised. A frost thermostat 30 can be fitted to the control unit 14 to override the time clock in the event of freezing temperatures.

Various modifications may be made to the embodiment without departing from the scope of the invention. For example the thyristors may be replaced by other solid state switches and the battery heaters could be replaced by any other suitable heating means.

Advantages of the invention are that fresh warm air is supplied to the house and condensation is minimised. Also, the use of solid state switches to control the battery heater is such that heating efficiency is maximised improving running costs

Claims

1. A central heating system comprising duct means having a filter and fan means for blowing cool fresh air through said filter, said cool fresh air being efficiently heated to provide a source of hot warm air.

2. A central heating system as claimed in claim 1, wherein said system also includes means for providing hot water.

3. Apparatus for controlling the efficiency of a central heating system, said apparatus comprising a control unit having temperature sensing means, solid state switch means being responsive to output signals from said temperature sensing means, said heating means coupled to an output of said solid state switch means for controlling the operation of said heating means in response to signals from said temperature sensing means.

4. Apparatus as claimed in claim 1, wherein said solid state switch means are thyristors and said temperature sensing means is a thermistor.

5. Apparatus as claimed in claim 3 or claim 4, wherein the thyristors are coupled to operafte electrical battery heaters.

6. Apparatus as claimed in any one of claims 3 to 5, wherein said thermistor is coupled to a temperature controller for setting a threshold temperature responsive to signals from said thermistor.

7. A system substantially as hereinbefore described with reference to the accompanying drawings.

8. Apparatus substantially as hereinbefore described with reference to the accompanying drawings.