Air Management

 

Managing circulation of air in a building, including its temperature, cleanness, and breathability, requires a special system.

Such system usually includes a gravity ventilation system, at least as a fallback system.

There are two networks of pipes in the building inflow and outflow. Water is taken from outflow network, heated or cooled, according the season, and pumped into the inflow network. When the building has a basement, it is convenient to use it for design and maintenance of these networks of pips pipes going horizontally could be in the basement. Pipes are usually insulated and buried in walls.

Radiators are plugged between these two networks using short access pipes. Valves controlling water flow through each radiator are placed in access pipes.

Such system could be augmented with perpetual supply of fresh air under pressure slightly higher than air pressure outside the building. This would support automatic venting of the air from the room. Supplied air could be heated or cooled according to the season. While this addition is rarely done in small buildings, it could be done relatively easily.

Advantage of such addition is ability to manage the level of oxygen in each room separately and to conduct quick venting of existing air in the room. Usually such venting is done by opening the windows, but, in some cases, it is not possible.

If we decide to make such addition, than we could improve air circulation in the room, by placing hot radiators and pipes delivering hot air on the bottom of the room and cold radiators and pipes delivering cold air on top of the room.

Due to heat transfer between a room and external environment, our system has to supply (remove) certain amount of heat to (from) the room. When temperature of water in the water inflow pipes and temperature of air in the air inflow pipes is fixed, the amount of heat transferred by the system is defined by the speed of water flow in the radiators and speed of delivered air inflow. This speed we control with valves.

This way, we could set temperature in the room by setting two valves controlling water inflow and controlling air inflow. This is not much different from existing water based systems.

However, when we are venting the room aggressively, this raises temperature in it in the winter, or drops temperature in it in the summer, dramatically. Sometimes even opening of a door in the room cannot help much. Hence, we need some additional mechanism to overcome this problem. We need better control of temperature of delivered in the room air. This could be done, if in addition to delivery of heated or cooled air, we separately deliver air at temperature outside of the building simply filtered external fresh air. Than we could combine two airstreams delivered in the room in proper proportions and control temperature of delivered air this way.

Thus, we need a bundle of pipes delivering air in a room, one pipe in this bundle should carry heated or cooled air, and the other pipe should always deliver fresh air at external air temperatures. In each room

Each of these pipes in a bundle should have its own valve to allow separate control of air delivery. In the end of this bundle should be a mixing cavity with opening into a room, which should have decorative covering the way it is done in gravity ventilation system.

Since we need to deliver heated air to the bottom of the room and cooled air to the top of the room, we need two such bundles in a room, one opening at the top and another at the bottom of the room.

We should handle air delivery the same way we handle water delivery using networks of air inflow pipes, to which pipes delivering air into each room air delivery access pipes, are connected. Hence, description above is description of air delivery access pipes.

For removal of air from rooms we need an air removal network of pipes in the building, with access pipes in each room connected to this network. Air should be removed from places, where air circulation is weak. In warm and in cold seasons, these places are different, hence it should be removed from different places in the room according to the season. Two air removal access pipes are needed in each room and they should be switched accordingly.

Because of the pumping of air into rooms, air in the rooms should be of pressure above atmospheric. This has at least two benefits. First, this difference of pressure should drive air removal, no pumping is needed. Second, excess of air pressure in the building should keep external dust away from it.

There is an additional factor, which has to be taken in consideration, when one designs such system. It is desirable to have different pipes carrying hot and cold water and different pipes carrying warm and cool air. This way, every season, about half of the system of pipes would be idle and available for examination and repair. Pipes would operate at smaller range of temperatures and more time would be available for system maintenance and repair.

Also, it is important to be able to switch the system between seasons in one place. This could be not trivial, when there are water-based and air-based subsystems, and when radiators and air delivery openings, serving during different seasons, are in different places.

Each component of this System has networks of pipes, which serve as a reservoir of water or air.

In closed circuit components, as water based components, two such networks are used and heating/cooling devices are plugged between them using inflow access pipes and outflow access pipes, with one of these access pipes having a valve. This way, one network becomes inflow network (into devices) and the other - outflow network (from devices) and a pump perpetually moves water (or some other substance) from outflow network into inflow network.

In open circuit components, as air based components, one such network is used and devices are connected just to this network using a pipe, also with a valve in it. Air (or another substance), is pumped into the network and released from these devices, or it is removed from the network and devices absorb the air (or another substance).

Following is description of one such Air Management System, which could be used in one family houses, as well as in large buildings, like hospitals, or apartment buildings.

Water Components

A Water Component of the System consists of:

        inflow and outflow networks of pipes filled with water,

        radiators with two access pipes connecting it to inflow and outflow networks,

        valves, one for a radiator, in one of the access pipes.

The system has two Water Components, one for hot water and another for cold water.

Air Components

The System has two Air Delivery Components, one for warm air and another for cold air. Each uses two-pipe bundles, where one pipe in a two-pipe bundle carries fresh air and the other carries either warm air or cooled air.

The Warm Air Delivery Component includes:

        warm air inflow network,

        fresh air inflow network,

        two-pipe access bundles providing access to the warm air inflow network and fresh air inflow network

        air mixers in these access bundles, where air from both pipes of two-pipe bundle is mixed,

        valves in both pipes of each access bundle,

        opening of air mixers into the room in each access bundle with covering as in ventilation system

 

The Cold Air Delivery Component is similar to Warm Air Delivery Component, only it includes cold air inflow network instead of warm air network.

The system also has two Air Removal Components, one used, when warm air is delivered, and another - when cold air is delivered.

Openings into rooms of these two types of Air Components are in different places in a room.

The Air Removal Component has an air outflow network of pipes and access pipes connecting this network to rooms, where access pipes have opening with covering, as in a ventilation system.

Management of Air Taken In

Air should be taken in from a place, where it is cleanest, for example, from the roof of a building.

It should be filtered and disinfected, for example, with use of UV light. Health improving fragrant substance should be added to it after that.

Management of Removed Air

Air in rooms should have pressure slightly higher than external air pressure. This pressure difference should move used air out of the room, while new air is pumped in.

Air, which is moving out should be first used for heat exchange with air prepared to be pumped into the rooms. This should be done before incoming air is heated or cooled.

After that, it should be used to support burning of fuel. Removed air has pressure higher than atmospheric pressure, hence, it useful during burning of fuel and useful during venting of products of burning.

Note, that this way, removed air is disinfected, which is important, when such system is used in a hospital, for example.

Placement of Inflow and Outflow Networks

Inflow and outflow networks of pipes have vertical pipes, usually insulated and placed inside the walls of the building, and horizontal pipes. The best place for horizontal pipes is in the basement and in the attic.

Seasonal Switch

Switch between heating and cooling seasons is done by simultaneous switching of inflow and outflow networks, because, in this system, different pipes are used in different seasons.

It was a goal of this design to allow simultaneous switching of Air and Water Components done in one place. This place should be where all inflow and outflow networks meet the place, where heating and cooling is done. This way, all systems could be switched in the same time.

Gravity ventilation system should be used during such switch, because air supply and removal systems are inoperable (for a short period).

After such switch, idle part of the system should be examined and repaired. It would be a lot of time to do that entire season.

During switching of Water Components, second Component is deployed and first Component is drained of water first and made ready for inspections and repairs. Air components are available for inspections and repairs immediately after the switch.

Water Components Functioning

A Water Component includes a set of radiators used for heating or cooling air in the building, with water of needed temperature running through them. Speed, with which it runs, and corresponding heat transfer rate, depend on settings of the valve in associated access pipe.

Water into radiators comes through an inflow network of pipes, in which water is pumped, and it flows from the radiators into an outflow network of pipes. From the outflow network water is taken, heated or cooled, depending on the type of the Component, and pumped back into the inflow network. Two access pipes connect a radiator to inflow and outflow networks:

        inflow access pipe connects inflow end of the radiator to the inflow network

        outflow access pipe connects outflow end of the radiator to the outflow network.

Taking water from the outflow network, heating it or cooling, and pumping it into the inflow network is done in one place in the building. where heating and cooling is done.

Traditionally, there is only one pair of networks (inflow and outflow). At the change of the season, the system is drained and water of different temperature starts circulation through it.

In this design, there are two pairs of networks and connected radiators, one for warm weather and another for cold weather two Water Components.

Radiators from different Water Components are placed in pairs: one provides heating and another provides cooling. Heating radiators are placed on the bottom of the wall, often under windows. Cooling radiators are placed on the top of the wall, often above windows.

Only one type of radiators (heating or cooling) in a time is operational, and, hence, only one Water Component is active in a time.

Air Components Functioning

Pressure of air after a mixer should be higher than in quarters, then air after mixing flows into a room naturally.

Pressure of air in the room should be higher than outside, then air flows out naturally and such elevated air pressure in the building keeps dust out of it.

There are two outflow Air Components, one for heating season and another for cooling season. Their outflow networks are almost identical and go in parallel, but they differ in their room access pipes. They are switched in the same place and time, where and when inflow Air Components are switched, i.e. when heating/cooling season is changed.

Openings of Outflow Air Components

Openings of outflow air components are placed where air circulation in the room is the worst this placement provides improvement of air circulation. When inflow Air Component delivers warm air to the bottom of a wall in a room, the corresponding outflow Air Component takes air from the bottom of an opposite wall. When inflow Air Component delivers cold air to the top of a wall in a room, the corresponding outflow Air Component takes air from the top of an opposite wall.

Control System

Combining effects of radiators and direct delivery of air to achieve desirable comfort requires fine control of speed of water flow through radiators and speed of flow of air, pumped into the room through the air mixer. To achieve this, valves have to be in pipes before water enters radiators and before air enters room.

The work of these valves is to constrict flow of air and water and this way cause change in speed of heat exchange between the system and air in the room.

Ability to control these valves manually should always be present, at least as a fallback system. However, it is desirable to have some computerized control system to do that. Such system should have ways to detect air temperature in the room and level of oxygen in the room. It would need to have some electronic interface, through which desirable settings could be provided and transmitted.

The control system would attempt to satisfy a request in bounds of its abilities. This might take some time, while the Control System tries different settings of valves and checks achieved results (adaptive control system). In any case, it should end up with parameters of the environment close to the requested ones.

Alexander Liss 7/16/2020