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System volume is important on any project using compressorized refrigeration in order to heat or cool building water. How much system volume is dependent on the equipment being used.

Some manufacturers require system volumes as high as 13gal/ton. They also advocate different volumes depending on the equipment type and/or application. We at Ecogreen advocate for 6gal/ton at a minimum on ou ASHP jobs regardless of the equipment used or the application it is serving.

You can always go with a larger gallons per ton for safety, and the only downside is a more sluggish system response. If it is hvac, then a bit less responsive is probably fine. However, if your application is process you may consider limiting the system water volume to improve responsiveness.

When calculating available system volume include both the primary water piping volume & secondary water piping volume that is active at all times. This means if a leg of piping isn't flowing then it cannot be counted in the total. Looking for the worst case minimum active flowing water through the system. Remember, the water is carrying the energy out to the building from the plant and back again.

While variable primary pumping can be achieved with the proper system design employed, we recommend primary/secondary with a decoupling to ensure the most reliable design/operation.

Primary/Secondary is achieved when the source (primary) is decoupled from the building (secondary). We can decouple with a pipe, with a 4 ported baffled storage tank, or with a gasketed plate heat exchanger.

When the source is decoupled the air source heat pumps only see constant flow through the refrigerant-to-water heat exchangers.

Primary Variable systems have no decoupler and vary the flow rate of water through the air source heat pump(s) actively.

We design around primary/secondary to limit this variable in order to provide the most reliable operation.

R513A (aka Opteon XP10) is a next generation refrigerant by Chemours. It is an A1 refrigerant meaning low toxicity and nonflammable. It is also zero ozone depleting & has a low GWP of 630. This refrigerant is Azeotropic meaning it is a blend, but with zero glide (which is good). This refrigerant is a mix of HFC (44% R134a) & HFO (56% R1234yf). POE oils are compatible with R513a.

It is a great balance of high performance, energy efficient, & environmentally sustainable. It has many applications but most notiably it is used in chillers and commercial refrigeration because it facilitates high lift & low suction applications.

A Dedicated Heat Recovery Chiller (DHRC) is a water-to-water chiller (aka water cooled chiller) optimized for heating (condenser side) and with sensors & control logic to control to the heating side or the cooling side, but not simultaneous control.

So you can only control to one side or the other at a time.

The hot side piping (sup/ret) & cold side piping (sup/ret) are always the same, just like a chiller.

You cannot provide heat unless you are also doing cooling, and vice versa.

Since the unit is not connected to a source loop its output is limited to smallest load of the 2 sides (heating or cooling depending on what you want to do).

And if there is no bms interface, then you must size it for the minimum cooling or heating loads that are always present.

High lift is important in heat pump heating mode as the temperature between the winter outdoor design and the hot water delivered can be well over 100F which is considered high lift. For example; when heating on a 0F winter day making 150F it can only be accomplished with Reciprocating compressors or with vapor injected scrolls. While reciprocating compressors are designed for this duty, scrolls can take a beating pushing these high lift conditions.

Semi-hermetic compressors (like Recips & Screws) can be opened for maintenance or repair while hermetic compressors (like scrolls) cannot be opened/repaired. Having semi-hermetic compressors allows us to fix in place.

Our shell box is similar to a shell & tube heat exchanger but in compact form with the tubes bending back & forth to accommodate a smaller footprint. Refrigerant runs in our tubes and water in the shell. The shell box can be opened in place for cleaning. The inside casing has a corrosion resistance coating and the tubes come in copper (standard), stainless steel, or titanium. Because it can be opened for cleaning and we do offer corrosion resistant components you can use the shell box for different types of water (it doesn't require clean water). For example, you may use it with a waste water source or application.

Yes, we do offer pumping packages.

We can provide primary circulating pumps to support our primary/secondary designs. We can also provide more hydronic features (al a carte) like buffer tanks (any size), gasketed plate heat exchangers, etc up to and including an entire pumping plant.

We provide these custom pumping packages inline with the ASHP but facilitate single in/out connections, single point power, and single point of control.

It depends on the size of the plant (tonnages in heating and/or cooling), what the plant is serving, how much redundancy you want baked into your design, and your construction budget.

For example, on larger tonnage buildings you may want a minimum of three so that if one is down for repair then you'll still have one that can dedicate to the cooling loop & one that can dedicate to the heating loop. This way you'll still be able to make cold & hot water.

But in another example you may have a small tonnage, not much real estate, a limited budget, and it's serving a single zone or AHU (like a DOAS unit). In this case, you may go with a single ASHP.

Hybrid designs make a lot of sense when the buildings are larger. A mix of air cooled chiller, 2pipe ASHPs, & a 4pipe ASHP typically makes a lot of sense when considering a typical buildings heating & cooling load profile.

In a typical office building (for example) there is usually a dominate cooling load in summer that is best served by an air cooled chiller which is optimized for cooling.

There is also typically a coincidental (simultaneous) heating & cooling loads through the year. The amount much be determined by analyzing an energy model of the building or estimating the maximum simultaneous loads. These simultaneous loads are served by the 4pipe (simultaneous) ASHP. But don't size it too large. Just because you can doesn't always mean you should. So consider a size that gains you enough heat recovery yet allows the 4pipe ASHP to run loaded a great deal of the year to ensure a timing payback against the added cost of a 4pipe ASHP.

The remaining heating load (above that of the 4pipe ASHP) will be covered by standard 2pipe (changeover) ASHPs.

yes- all Ecogreen product meets or exceeds the ASHRAE std 90.1 2019 efficiency standard

We can provide ship loose supply & return piping headers for field assembly. They are mounted outside the frame but close fitted near the frame. These water inlet/outlet is centered and perpendicular to that side of the unit.

we can provide plastic or steel headers, and they can come with isolation/balancing valves as necessary.

We advocate constant full flow through our units in primary/secondary configuration. Because we have large liquid receivers & high turndown (vfds on each compressor), we can run water through inactive modules.

However, please note that the leaving water temperature from the unit will be higher than the active module leaving water as the active & inactive water paths mix. This is typically not an issue as lower loads can typically accept higher water temperature. But in cooling you may require colder water for a particular space or zone (like a data room). Know that in these cases we can devise a discharge temperature reset to accomodate.

Most part load applications allow lower discharge temperatures in heating but there are some occasions where low load operation requires high discharge LWT on a warmer day (140F LWT with an ambient of 50F). In this case we are limited to 50% turndown.

We can place the electrical control panel on either end of the ASHP. Because we can do this we can offer two separate ashp's end-to-end for a 2nd power feed.

For example, you have a size 100 but you want emergency power to some of the modules. You can split this design into 2 separate units like (2) 050's placed against each other with opposite side control panels. This way it takes the same footprint and achieves dual power feed. Or you could do (1) 075 & (1) 025 for the same effect, either way there is no cost difference than when you did a single size 100.